Cellulose: Development, Processing, and Applications [1 ed.] 1032414383, 9781032414386

Table of contents :
Cover
Half Title
Title Page
Copyright Page
Dedication
Table of Contents
Preface
About the Editors
List of Contributors
Chapter 1 Introduction
References
Chapter 2 A Brief Overview of the Use of Bamboo Biomass in the Asian Region's Energy Production
Introduction
The Benefits of Bamboo as a Potential Source of Biomass
An Analysis of the Viability of Bamboo Biomass as a Source of Energy
In Comparison with Other Forms of Renewable Energy
Emissions of Greenhouse Gases
Water Consumption
Accessibility
Land Usage
Restriction Imposed by Technology
In Comparison with Other Forms of Energy Crops
Methods for Extracting Energy From Bamboo's Biomass
Thermochemical Conversion
Pyrolysis
Gasification
Direct Combustion
Biochemical Conversion
The Present Situation Regarding the Use of Bamboo Biomass for the Generation of Energy
Malaysia
Indonesia
Thailand
Vietnam
Japan
Conclusion
References
Chapter 3 Pre-Treatment of Oil Palm Empty Fruit Bunches with Sea Water Improves the Qualities of Lignocellulose Biomass
Introduction
Oil Palm Biomass: Lignocellulosic Material Characteristics
Biomass Fractionation in Sea Water
Halophilic Enzymes Challenge Seawater-Based Biocatalysis in Biorefineries
Building Components in Lignocellulosic Biorefineries Based on Sea Water
Conclusion
References
Chapter 4 Biorefinery of Biofuel Production: Thermochemical and Biochemical Technologies From Renewable Resources
Introduction
Biofuel Feedstocks
Thermochemical Conversion
Pyrolysis
Slow Pyrolysis
Fast Pyrolysis
Flash Pyrolysis
Pyrolysis Technology
Vacuum Pyrolysis
Plasma Pyrolysis
Hydrothermal Liquefaction
Gasification
Gasification Parameters
Effect of Feedstock Types
Effect of Temperature
Fischer–Tropsch Catalytic Reaction
Biochemical Conversion
Pretreatment
Physical Pretreatment
Chemical Pretreatment
Biological Pretreatment
Enzymatic Hydrolysis
Biofuel Production Via Biochemical Route
Bioethanol
Biobutanol
Biohydrogen
Conclusion and Future Outlook
References
Chapter 5 Review on the Current Updates on Palm Oil Industry and Its Biomass Recycling to Fertilizer in Malaysia
Introduction
Oil Palm Industry in Malaysia
Palm Oil Waste in Malaysia
Utilization of Palm Oil Waste
Conversion of Palm Oil Waste Into Fertilizer
Conclusion and Future Prospect
References
Chapter 6 Wastewater as Nutrient Enhancer and Moisturizer for Compost Production: A Review
Introduction
Methodology
Industrial Wastewater Characteristics
Nutrient Enhancer and Moisturizer in Composting
POME
Olive Mill Wastewater (OMW)
Alcohol/Molasses Distillery Wastewater (DSW)
Swine Wastewater
TL Wastewater
Monosodium Glutamate Wastewater (MSGW)
Summary of the Wastewater Application for Composting
Challenges and Future Perspectives
Conclusion
Acknowledgment
References
Chapter 7 Biocomposites as Structural Components in Various Applications
Introduction on Biocomposite
Natural Fiber as Reinforced in a Biocomposite
Modification of Natural Fiber Through Chemical Treatment
Biodegradable Polymer
Polylactic Acid (PLA)
Polyhydroxyalkanoates (PHA)
Biocomposites as Structural Components in Various Applications
Structural Components in Automotive
Structural Components in Building and Construction
Structural Components in Furniture and Decorative Panels
Performances of Biocomposite
Manufacturing of Biocomposite
Compressing Molding
Extrusion
Injection Molding
Long Fiber Thermoplastic-Direct (LFT-D) Method
Resin Transfer Molding (RTM)
Pultrusion
Challenges and Opportunities
Conclusion
References
Chapter 8 Natural Fiber Composites for Automotive Applications
Introduction
Classifications of Natural Fiber
Natural Fiber Composites
Reinforced Polymer Composites
Manufacturing Process
Compression Molding
Resin-Transfer Molding (RTM)
Extrusion
Injection Molding
Matrix Material
Thermoplastic Matrix
Thermosets Matrix
Applications in Automotive Industry
History
Advantages of Natural Fiber Composites in Automotive Industry
Market Demand and Future Perspectives
Conclusion
References
Chapter 9 Cellulose Nanocrystals From Agro Residues as Reinforcing Agent in Nanocomposites
Introduction
Sustainability Factors
Cellulose Materials
Cellulose Nanocrystals (CNCs)
Cellulose Nanocrystals (CNCs) Extraction
Oxidation
Enzymatic
Acid Hydrolysis
Cellulose Nanocrystals as Nanocomposites
Thermal Behavior of Cellulose Nanocrystals
Conclusions
Acknowledgments
References
Chapter 10 All-Cellulose Composites: Processing, Properties, and Applications
Introduction
Processing Routes
Impregnation
Partial Surface Dissolution
Applications
Composites
Packaging
Fibers and Filaments
Bioengineering and Biomedical Materials
Dye and Heavy Metal Ion Adsorbents
Recycling, Sustainability, and Biodegradability
Conclusions and Prospects
References
Chapter 11 Cellulose-Based Bioadhesive for Wood-Based Composite Applications
Introduction
Cellulose
Properties of Cellulose
Physical and Mechanical Properties of Cellulose
Chemical Properties of Cellulose
Thermal and Electrical Properties of Cellulose
Cellulose Modification for Adhesives Production
Cellulose-Based Adhesives for Wood-Based Composites
Dialdehyde Cellulose (DAC)
Methyl Cellulose
Cellulose Nanofibrils
Performance of Cellulose-Based Bioadhesive for Wood-Based Composites
Challenges and Opportunities
Conclusion
References
Chapter 12 Deriving Renewable Feedstock From Palm Oil Mill Effluent for Polyhydroxyalkanoate (PHA) Production
Introduction
Biodegradable Polymer
Polyhydroxyalkanoate (PHA)
VFA Generation
PHA Production Pathway
PHA Accumulating Microorganisms
PHA Applications
Latest Trends in Producing PHA From POME
Conclusions
Acknowledgment
References
Chapter 13 Recent Developments in Pre-Treatment and Nanocellulose Production From Lignocellulosic Materials
Introduction
Lignocellulosic Material
Classification of Lignocellulosic Raw Materials
Nanocellulose
Classification of Nanocellulose
Nanocrystalline Cellulose (NCC)
Nanofibrillated Cellulose (NFC)
Isolation of Nanocellulose
Pre-Treatment of Lignocellulosic Raw Materials
Pre-Treatment of Cellulosic Material
Chemical Pre-Treatment
Alkaline Pre-Treatment
Biological Pre-Treatment
Enzyme-Assisted Hydrolysis
Physicochemical Pre-Treatment
Hydrothermolysis
Mechanical Treatment
Homogenization
Mechanical Homogenization
Chronological Events/Related Studies
Conclusion
References
Chapter 14 Characteristics of Cellulose Nanocrystals From Sugarcane Bagasse Isolated From Various Methods: A Review
Introduction
Bagasse Cellulose and Nanocellulose
Cellulose
Cellulose Nanocrystals
Cellulose Nanocrystals Isolation
Pretreatment Methods on Bagasse
Alkaline Treatment
Biological Treatment (Enzymatic Method)
The Isolation Method of Cellulose Nanocrystals
Chemical Treatment (Acid Hydrolysis)
TEMPO (2,2,6,6-Tetramethylpiperidin-1-Oxy)
Mechanical Treatment (High-Pressure Homogenization)
Mechanical Treatment (High-Intensity Ultrasonication)
Characterization of Bagasse Cellulose Nanocrystals
Yield
Morphology
Crystallinity Index
Conclusion
References
Chapter 15 Applications of Regenerated Cellulose Products
Introduction
Cellulose Insolubility, Dissolution, and Regeneration Process
Regenerated Cellulose Products
Hydrogel, Aerogel, Xerogel, Cryogel
Fibers
Membrane and Thin Films
Applications
Medical
Agricultural
Automotive
Aerospace
Textile
Conclusion
Acknowledgments
References
Chapter 16 Developments and Applications of Nanocellulose-Based Hydrogels in the Biomedical Field
Introduction
Nanocellulose-Based Hydrogels: Structure and Properties
Nanocellulose-Based Hydrogels in Biomedical Applications
Drug Delivery
Tissue Engineering
Wound Dressing and Wound Healing
Biomonitoring and Biosensing
Conclusion
References
Chapter 17 Overview of Cellulose Fiber as Materials for Paper Production
Introduction
Cellulose Fiber Sources
Wood
Non-Wood
Recycled Fiber
Rags
Pulp and Paper Manufacturing Process in Paper Industry
Pulping Methodology
Mechanical Pulping
Chemi-Mechanical Pulping
Semi-Chemical Pulping
Chemical Pulping
Bio Pulping
Bleaching
Pulp Blending
Pulp Beating/Refining
Additives
Papermaking
Forming and Dewatering
Pressing
Drying
Calendering
Reeling and Winding
Conclusion
References
Chapter 18 Challenges and State of the Art of Allium Pulp Development for Papermaking: A Brief Review
Introduction
Allium Peels as Raw Pulp for Paper
Papermaking Technology
Prospective of Allium Peels as a Paper Pulp
Conclusion
References
Chapter 19 Application of Cellulose in Leather
Introduction
Leather Processing
Beamhouse
Tanning
Finishing
Tanning
Retanning
Finishing
Leather Solid Wastes
Application of Cellulose in Leather Processing
Cellulose in Tanning
Cellulose in Retanning
Cellulose in Finishing
Composites of Cellulose and Solid Leather Waste
Conclusion
References
Chapter 20 Utilization of Cellulose in Wastewater Treatment
Introduction
Forms of Cellulose
Modification of Cellulose
Overview
Types of Cellulose Modification
Dissolution of Cellulose
Allomorphic Modification
Derivation of Cellulose
Modified Cellulose for Effluent Treatment
The Challenge and Concern of Using Cellulose in Wastewater Treatment
References
Chapter 21 Comparing Properties and Potential of Pinewood, Dried Tofu, and Oil Palm Empty Fruit Bunch (EFB) Pellet as Cat Litter
Introduction
Materials
Source of Biodegradable Cat Litter
Methods
Odor Recognition Test
Results and Discussion
Physical Properties
Adsorption Rate, Total Volume of Water Adsorption, and Hydration Capacities
Odor Sensory Test
Conclusion
References
Chapter 22 Challenges and Future Perspectives
References
Index

Citation preview

Cellulose Cellulose: Development, Processing, and Applications covers topics related to advanced cellulose development and processing, as well as the utilization of major agricultural and biomass waste. It discusses the utilization of cellulose from other agricultural and biomass materials, including oil palm biomass, bamboo, and other non-wood forest products in emerging areas. It covers the treatments used to improve the quality of cellulosic materials in specific applications. Following that, the book delves into the use of cellulosic materials in the application of composting science and technology. Features: • Delves into the specific agriculture waste/biomass waste materials used for the advanced cellulose-based production • Outlines the potential use of the covered materials for energy production and other emerging applications • Includes composting technology and processes using cellulosic materials • Overviews industrial applications of cellulose from agricultural waste/biomass waste and composting technology • Discusses the main agricultural waste/biomass in the Asian region This book is aimed at researchers and graduate students in chemical engineering, bioprocessing, composites, and biotechnology.

Cellulose

Development, Processing, and Applications

Edited by

Abu Zahrim Yaser, Mohd Sani Sarjadi, and Junidah Lamaming

Designed cover image: Junidah Lamaming First edition published 2024 by CRC Press 6000 Broken Sound Parkway NW, Suite 300, Boca Raton, FL 33487-2742 and by CRC Press 4 Park Square, Milton Park, Abingdon, Oxon, OX14 4RN CRC Press is an imprint of Taylor & Francis Group, LLC © 2024 selection and editorial matter, Abu Zahrim Yaser, Mohd Sani Sarjadi, and Junidah Lamaming; individual chapters, the contributors Reasonable efforts have been made to publish reliable data and information, but the author and publisher cannot assume responsibility for the validity of all materials or the consequences of their use. The authors and publishers have attempted to trace the copyright holders of all material reproduced in this publication and apologize to copyright holders if permission to publish in this form has not been obtained. If any copyright material has not been acknowledged, please write and let us know so we may rectify in any future reprint. Except as permitted under U.S. Copyright Law, no part of this book may be reprinted, reproduced, transmitted, or utilized in any form by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying, microfilming, and recording, or in any information storage or retrieval system, without written permission from the publishers. For permission to photocopy or use material electronically from this work, access www.copyright.com or contact the Copyright Clearance Center, Inc. (CCC), 222 Rosewood Drive, Danvers, MA 01923, 978-750-8400. For works that are not available on CCC please contact [email protected] Trademark notice: Product or corporate names may be trademarks or registered trademarks and are used only for identification and explanation without intent to infringe. ISBN: 9781032414386 (hbk) ISBN: 9781032414393 (pbk) ISBN: 9781003358084 (ebk) DOI: 10.1201/9781003358084 Typeset in Times by codeMantra

We dedicate this book to our family, friends, and researchers who are always passionate about sharing, crowdsourcing, and gaining knowledge to build a sustainable future.

Contents Preface...............................................................................................................................................xi About the Editors............................................................................................................................ xiii List of Contributors........................................................................................................................... xv Chapter 1 Introduction...................................................................................................................1 Abu Zahrim Yaser and Junidah Lamaming Chapter 2 A Brief Overview of the Use of Bamboo Biomass in the Asian Region’s Energy Production.........................................................................................................7 Siti Ayu Aziz and Mohd Sani Sarjadi Chapter 3 P ­ re-​­Treatment of Oil Palm Empty Fruit Bunches with Sea Water Improves the Qualities of Lignocellulose Biomass........................................................................... 27 Siti Ayu Aziz, Sabrina Soloi, Mohd Hafiz Abd Majid, Juferi Idris, Md Lutfor Rahman, and Mohd Sani Sarjadi Chapter 4 Biorefinery of Biofuel Production: Thermochemical and Biochemical Technologies from Renewable Resources................................................................... 45 Tan Kean Meng, Muaz Mohd Zaini Makhtar, Muhammed Aidiel Asyraff Mohmad Hatta, and Mohd Asyraf Kassim Chapter 5 Review on the Current Updates on Palm Oil Industry and Its Biomass Recycling to Fertilizer in Malaysia............................................................................. 71 Rozelyn Ignesia Raymond and Khim Phin Chong Chapter 6 Wastewater as Nutrient Enhancer and Moisturizer for Compost Production: A Review..................................................................................................................... 83 Abu Zahrim Yaser and Junidah Lamaming Chapter 7 Biocomposites as Structural Components in Various Applications.......................... 105 Nurjannah Salim and Siti Norbaini Sarmin Chapter 8 Natural Fiber Composites for Automotive Applications........................................... 119 Noor Afeefah Nordin Chapter 9 Cellulose Nanocrystals from Agro Residues as Reinforcing Agent in Nanocomposites........................................................................................................ 131 Santhana Krishnan, Dianah Mazlan, Mohd Fadhil MD Din, Mohd Nasrullah, and Sumate Chaiprapat vii

viii

Contents

Chapter 10 ­All-​­Cellulose Composites: Processing, Properties, and Applications...................... 145 Supachok Tanpichai Chapter 11 ­Cellulose-​­Based Bioadhesive for ­Wood-​­Based Composite Applications................. 163 Ahsan Rajib Promie, Afroza Akter Liza, Md Nazrul Islam, Atanu Kumar Das, Md Omar Faruk, Sumaya Haq Mim, and Kallol Sarker Chapter 12 Deriving Renewable Feedstock from Palm Oil Mill Effluent for Polyhydroxyalkanoate (­PHA) Production................................................................. 175 Gobi Kanadasan, Vel Murugan Vadivelu, and Muaz Mohd Zaini Makhtar Chapter 13 Recent Developments in ­Pre-​­Treatment and Nanocellulose Production From Lignocellulosic Materials.......................................................................................... 185 Asniza Mustapha, Mohd Fahmi Awalludin, Wan Noor Aidawati Wan Nadhari, and Nur Izzaati Saharudin Chapter 14 Characteristics of Cellulose Nanocrystals from Sugarcane Bagasse Isolated from Various Methods: A Review............................................................................. 201 Eti Indarti, Zalniati Fonna Rozali, Dewi Yunita, Laila Sonia, and Marwan Mas Chapter 15 Applications of Regenerated Cellulose Products...................................................... 217 Kushairi Mohd Salleh, Nur Amira Zainul Armir, Swarna Devi Palanivelu, Amalia Zulkifli, and Sarani Zakaria Chapter 16 Developments and Applications of ­Nanocellulose-​­Based Hydrogels in the Biomedical Field....................................................................................................... 237 Junidah Lamaming, Sofie Zarina Lamaming, Mohd Hazim Mohamad Amini, and Abu Zahrim Yaser Chapter 17 Overview of Cellulose Fiber as Materials for Paper Production.............................. 253 Nurul Syuhada Sulaiman Chapter 18 Challenges and State of the Art of Allium Pulp Development for Papermaking: A Brief Review.......................................................................................................... 269 Mohammad Harris M. Yahya and Noor Azrimi Umor Chapter 19 Application of Cellulose in Leather.......................................................................... 277 Victória Vieira Kopp, Vânia Queiroz, Mariliz Gutterres and João Henrique Zimnoch dos Santos Chapter 20 Utilization of Cellulose in Wastewater Treatment.................................................... 287 Nur Syazwani Abd Rahman and Norhafizah Saari

ix

Contents

Chapter 21 Comparing Properties and Potential of Pinewood, Dried Tofu, and Oil Palm Empty Fruit Bunch (­EFB) Pellet as Cat Litter.......................................................... 301 Noor Azrimi Umor, Nurul Hidayah Adenan, Nadya Hajar, Nurul Ain Mat Akil, Nor Haniah A. Malik, Shahrul Ismail, and Zaim Hadi Meskam Chapter 22 Challenges and Future Perspectives..........................................................................309 Junidah Lamaming, Abu Zahrim Yaser, and Mohd Sani Sarjadi Index............................................................................................................................................... 313

Preface Cellulose, as a next-generation material, will evolve in terms of its research and developments, spurred on by technological innovation. Cellulose is used in a wide range of applications, including paper, textiles, construction materials, food additives, bulking agents, and pharmaceuticals. It is also a promising renewable resource for the production of biofuels, bioplastics, compost, and other sustainable materials. The adoption of the Sustainable Development Goals as a vision has established a framework toward a more sustainable future. Given that it can be efficiently recovered not just from wood but also from agricultural waste or lignocellulosic materials, it looks promising as a sustainable resource with a low environmental impact. This eco-friendly material has the potential to address resource depletion experienced by many sectors. However, recent advances in cellulose chemistry and processing have opened up new opportunities for its use in emerging technologies, such as biocomposites, energy storage, and the biomedical field. The book Cellulose: Development, Processing, and Applications aims to provide an in-depth overview of the current knowledge of cellulose and its many promising applications. This book covers a wide range of issues related to cellulose, from its molecular structure and synthesis through its processing into various forms, such as all-cellulose and nanocellulose, and its regeneration, as well as its diverse applications in different industries. Future research directions are also outlined, along with a discussion of current issues and potential solutions associated with the development of cellulose-based products. It also features a variety of processing methods, including mechanical and thermal conversion, as well as chemical and enzymatic modification. The book also delves into the various applications of cellulose, including its use in paper, textiles, construction materials, automotive applications, leather processing, and absorption materials in wastewater. It explores the emerging trends in cellulose research, including new methods for cellulose regeneration. It highlights emerging cellulose-relevant research such as new cellulose production methods, the development of innovative cellulose-based products, and the implementation of cellulose into new technologies. The chapters in this book have been written by experts in the field of cellulose research, including scientists from academia, industry, and government research organizations. The contributors have been invited based on their expertise and their contributions to the field of cellulose research. It will be of interest to researchers working on cellulose-based materials and their applications, as well as its potential for new and innovative applications. The book will also be a valuable resource for engineers, technologists, and students in materials science, chemistry, biology, and related fields. We hope that this book will not only contribute to the corpus of cellulose research and societal knowledge but also benefit future generations who aspire to enhance and improve the way they live through sustainable living. We extend our gratitude to the reviewers: AA Rushdan, AH Abdul Hair, AZM Asa’ari, A Ahmad, A Embrandiri, JG Boon, CK Saurabh, HK Abdul Razak, MH Mohd Roslim, J Lamaming, MN Islam, CH Ng, NI Saharudin, R Alkarimiah, SF Mhd Ramle, S Saallah, T Simioni, TNH Tuan Ismail, and ZA Abdul Hamid for their valuable comments and suggestions for the chapters in this book. Editors Abu Zahrim Yaser Mohd Sani Sarjadi Junidah Lamaming

xi

About the Editors Abu Zahrim Yaser, PhD is an Associate Professor in Waste Processing Technology at the Faculty of Engineering, Universiti Malaysia Sabah, Malaysia. He obtained his PhD from Swansea University. He has published 12 books and more than 100 other publications. His inventions in the composting systems have been adopted by Tongod and Nabawan districts in Sabah. He is the co-chair for Kundasang’s Community Composting Site, a site dedicated for vegetable waste composting. He is a visiting scientist at the University of Hull. Mohd Sani Sarjadi, PhD is currently an Associate Professor in Industrial Chemistry in the Faculty of Science and Natural Resources, Universiti Malaysia Sabah. His PhD was awarded in 2015 and obtained from the University of Sheffield, United Kingdom. His research interests include organic synthesis, polymer chemistry, and all aspects of industrial chemistry. He had published numerous articles in local and international refereed journals and conference proceedings. He is an Associate Member of the Royal Society of Chemistry, United Kingdom (Chartered Chemist); Associate Member of the Malaysian Institute of Chemistry; and Professional Technologist (Material Science Technology), Malaysia Board of Technologists. Junidah Lamaming, PhD is currently a fellow researcher at the Faculty of Engineering, Universiti Malaysia Sabah. She obtained her PhD in 2016 in the field of nanocellulose and nanofiber science and technology from Universiti Sains Malaysia, Malaysia. She was rewarded an IAAM Scientist Award from International Association of Advanced Materials. Her research interests include nanocellulose fiber and applications, polymer blends, reinforced/filled polymer composites, characterization and production of lignocellulose-based composites and fireretardants, bioadhesives, and biopolymers using sustainable methods. Over the years, she has published articles in a significant number of high impact journals, conference papers, and a book in her related research areas. She also contributes her expertise and knowledge by reviewing international and national publications. She is a member of the Malaysia Board of Technologists.

xiii

List of Contributors Nurul Hidayah Adenan Faculty of Applied Science Universiti Teknologi MARA Cawangan Negeri Sembilan Kuala Pilah, Malaysia

Atanu Kumar Das Department of Forest Biomaterials and Technology Swedish University of Agricultural Sciences Umeå, Sweden

Nurul Ain Mat Akil Faculty of Applied Science Universiti Teknologi MARA Cawangan Negeri Sembilan Kuala Pilah, Malaysia

Mohd Fadhil MD Din Centre for Environmental Sustainability and Water Security (IPASA), School of Civil Engineering, Faculty of Engineering Universiti Teknologi Malaysia Skudai, Malaysia

Mohd Hazim Mohamad Amini Faculty of Bio-Engineering and Technology Universiti Malaysia Kelantan Jeli, Malaysia Nur Amira Zainul Armir Bioresources and Biorefinery Laboratory, Department of Applied Physics, Faculty of Science and Technology Universiti Kebangsaan Malaysia Bangi, Malaysia Mohd Fahmi Awalludin Forest Products Division Forest Research Institute Malaysia Kepong, Malaysia Siti Ayu Aziz Faculty of Science and Natural Resources Universiti Malaysia Sabah Kota Kinabalu, Malaysia Sumate Chaiprapat Faculty of Engineering, Department of Civil and Environmental Engineering, PSU Energy Systems Research Institute (PERIN) Prince of Songkla University Songkhla, Thailand Khim Phin Chong Faculty of Science and Natural Resources Universiti Malaysia Sabah Kota Kinabalu, Malaysia

Md Omar Faruk Forestry and Wood Technology Discipline Khulna University Khulna, Bangladesh Mariliz Gutterres Chemical Engineerin Department, Laboratory for Leather and Environmental Studies Federal University of Rio Grande do Sul Porto Alegre, Brazil Nadya Hajar Faculty of Applied Science Universiti Teknologi MARA Cawangan Negeri Sembilan Kuala Pilah, Malaysia Muhammed Aidiel Asyraff Mohmad Hatta Bioprocess Technology Division, School of Industrial Technology, Universiti Sains Malaysia Renewable Biomass Transformation Cluster, School of Industrial Technology, Universiti Sains Malaysia Penang, Malaysia Juferi Idris School of Chemical Engineering, College of Engineering Universiti Teknologi MARA (UiTM) Kota Samarahan, Malaysia

xv

xvi

List of Contributors

Eti Indarti Agricultural Product Technology Department, Faculty of Agriculture Universitas Syiah Kuala Banda Aceh, Indonesia

Junidah Lamaming Chemical Engineering Programme, Faculty of Engineering Universiti Malaysia Sabah Kota Kinabalu, Malaysia

Md Nazrul Islam Forestry and Wood Technology Discipline Khulna University Khulna, Bangladesh

Sofie Zarina Lamaming Bioresource Technology Division, School of Industrial Technology Universiti Sains Malaysia Penang, Malaysia

Shahrul Ismail Institute of Tropical Aquaculture and Fisheries University Malaysia Universiti Malaysia Terengganu Kuala Nerus, Malaysia Gobi Kanadasan Department of Petrochemical Engineering, Faculty of Engineering and Green Technology Universiti Tunku Abdul Rahman Kampar, Malaysia Mohd Asyraf Kassim Bioprocess Technology Division, School of Industrial Technology, Universiti Sains Malaysia Renewable Biomass Transformation Cluster, School of Industrial Technology, Universiti Sains Malaysia Penang, Malaysia Victória Vieira Kopp Chemical Engineering Department, Laboratory for Leather and Environmental Studies Federal University of Rio Grande do Sul Porto Alegre, Brazil Santhana Krishnan Faculty of Engineering, Department of Civil and Environmental Engineering, PSU Energy Systems Research Institute (PERIN) Prince of Songkla University Songkhla, Thailand

Afroza Akter Liza Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forest Resources and Joint International Research Lab of Lignocellulosic Functional Materials Nanjing Forestry University Nanjing, China Mohd Hafiz Abd Majid Faculty of Science and Natural Resources Universiti Malaysia Sabah Kota Kinabalu, Malaysia Muaz Mohd Zaini Makhtar Bioprocess Technology Division, School of Industrial Technology, Universiti Sains Malaysia Renewable Biomass Transformation Cluster, School of Industrial Technology, Universiti Sains Malaysia Centre of Innovation and Consultation, Universiti Sains Malaysia Penang, Malaysia Nor Haniah A. Malik Faculty of Applied Science Universiti Teknologi MARA Cawangan Negeri Sembilan Kuala Pilah, Malaysia Marwan Mas Chemical Engineering Department, Faculty of Engineering Universitas Syiah Kuala Banda Aceh, Indonesia

xvii

List of Contributors

Dianah Mazlan School of Civil Enginnering Universiti Sains Malaysia, Engineering Campus Nibong Tebal Penang, Malaysia Tan Kean Meng Bioprocess Technology Division, School of Industrial Technology, Universiti Sains Malaysia Penang, Malaysia Renewable Biomass Transformation Cluster, School of Industrial Technology, Universiti Sains Malaysia Penang, Malaysia Zaim Hadi Meskam Usaha Strategik Sdn. Bhd. Puchong, Malaysia Sumaya Haq Mim Forestry and Wood Technology Discipline Khulna University Khulna, Bangladesh Asniza Mustapha Forest Products Division Forest Research Institute Malaysia Selangor, Malaysia Wan Noor Aidawati Wan Nadhari Malaysian Institute of Chemical and Bioengineering Technology Universiti Kuala Lumpur Melaka, Malaysia Mohd Nasrullah Faculty of Civil Engineering Technology Universiti Malaysia Pahang (UMP) Kuantan, Malaysia Noor Afeefah Nordin Institute of Power Engineering Universiti Tenaga Nasional Kajang, Malaysia

Swarna Devi Palanivelu Department of Biological Sciences and Biotechnology, Faculty of Science and Technology Universiti Kebangsaan Malaysia Bangi, Malaysia Ahsan Rajib Promie Department of European Biorefinery Université de Technologie de Troyes Troyes, France Vânia Queiroza Chemical Engineering Department, Laboratory for Leather and Environmental Studies Federal University of Rio Grande do Sul Porto Alegre, Brazil Md Lutfor Rahman Faculty of Science and Natural Resources Universiti Malaysia Sabah Kota Kinabalu, Malaysia Nur Syazwani Abd Rahman Bioresource Technology Division, School of Industrial Technology Universiti Sains Malaysia Penang, Malaysia Rozelyn Ignesia Raymond Faculty of Science and Natural Resources Universiti Malaysia Sabah Kota Kinabalu, Malaysia Zalniati Fonna Rozali Agricultural Product Technology Department, Faculty of Agriculture, Universitas Syiah Kuala Master Program of Agriculture Industrial Technology, Faculty of Agriculture, Universitas Syiah Kuala Banda Aceh, Indonesia Norhafizah Saari Bioresource Technology Division, School of Industrial Technology Universiti Sains Malaysia Penang, Malaysia

xviii

List of Contributors

Nur Izzaati Saharudin Bioresource Technology Division, School of Industrial Technology Universiti Sains Malaysia Minden, Malaysia

Laila Sonia Master Program of Agriculture Industrial Technology, Faculty of Agriculture Universitas Syiah Kuala Banda Aceh, Indonesia

Nurjannah Salim Faculty of Industrial Sciences and Technology Universiti Malaysia Pahang Kuantan, Malaysia

Agency for Regional Development Province of Aceh, Indonesia

Kushairi Mohd Salleh Bioresource Technology Division, School of Industrial Technology, Universiti Sains Malaysia Renewable Biomass Transformation Cluster, School of Industrial Technology, Universiti Sains Malaysia Penang, Malaysia João Henrique Zimnoch dos Santos Chemistry Institute Federal University of Rio Grande do Sul Porto Alegre, Brazil Mohd Sani Sarjadi Faculty of Science and Natural Resources Universiti Malaysia Sabah Kota Kinabalu, Malaysia Kallol Sarker Forestry and Wood Technology Discipline Khulna University Khulna, Bangladesh Siti Noorbaini Sarmin Department of Wood Industry, Faculty of Applied Sciences Universiti Teknologi MARA Pusat Jengka, Malaysia Sabrina Soloi Faculty of Science and Natural Resources Universiti Malaysia Sabah Kota Kinabalu, Malaysia

Nurul Syuhada Sulaiman Bioresource Technology Division, School of Industrial Technology Universiti Sains Malaysia Penang, Malaysia Supachok Tanpichai Learning Institute, King Mongkut’s University of Technology Thonburi Cellulose and Bio-based Nanomaterials Research Group, King Mongkut’s University of Technology Thonburi Bangkok, Thailand Noor Azrimi Umor Faculty of Applied Science Universiti Teknologi MARA Cawangan Negeri Sembilan Kuala Pilah, Malaysia Vel Murugan Vadivelu School of Chemical Engineering Universiti Sains Malaysia Nibong Tebal, Malaysia Mohammad Harris M. Yahya Faculty of Applied Science Universiti Teknologi MARA Cawangan Negeri Sembilan Kuala Pilah, Malaysia Abu Zahrim Yaser Chemical Engineering Programme, Faculty of Engineering Universiti Malaysia Sabah Kota Kinabalu, Malaysia

List of Contributors

Dewi Yunita Agricultural Product Technology Department, Faculty of Agriculture, Universitas Syiah Kuala Master Program of Agriculture Industrial Technology, Faculty of Agriculture, Universitas Syiah Kuala Banda Aceh, Indonesia Sarani Zakaria Bioresources and Biorefinery Laboratory, Department of Applied Physics, Faculty of Science and Technology Universiti Kebangsaan Malaysia Bangi, Malaysia

xix

Amalia Zulkifli Bioresources and Biorefinery Laboratory, Department of Applied Physics, Faculty of Science and Technology Universiti Kebangsaan Malaysia Bangi, Malaysia

1

Introduction Abu Zahrim Yaser and Junidah Lamaming Universiti Malaysia Sabah

CONTENT References...........................................................................................................................................6 Cellulose, as the main biopolymers derived from either wood or lignocellulosic materials, can be utilized in diversified products in various applications, including the energy, food and beverage industries, pharmaceutical and biomedical fields, pulp and paper industries, electric and electronic industries, as well as construction. In a report on the cellulose market, Pulidindi and Prakash of Future Business Insights (­2022) estimated that the market was worth USD 219.53 billion in 2018 and that it would expand by 4.2% between 2018 and 2026 to reach USD 305.08 billion. Growing consumer demand and the development of cellulose usage and its derivatives boost increased production. Technology and engineering evolution have prompted the advanced development of new methods, inventions as well as new products which are greener and more sustainable. For example, food and beverage applications are being driven by rising demand for processed foods such as ­ready-­​­­to-​­eat meals and bakery products. Furthermore, a shift in consumer preference for ­plant-​ ­based ingredients in personal care and cosmetics is spurring market product development. This has led to the introduction and usage of sustainable ­non-­​­­wood-​­based alternatives made from agricultural waste. This lignocellulosic biomass includes oil palm fibers, rice husks and stalks, banana stems, bamboo, corn stalks, walnut shells, kenaf, bagasse, hemp fibers, and others. In this book, a few lignocellulosic biomasses development, processing method, and application of cellulose have been highlighted. Among them are bamboo, oil palm wastes, including empty fruit bunches (­EFB) and palm oil mill effluent (­POME), allium (­onion) peels, as well as sugarcane bagasse. This ­cellulose-​­rich material can be processed further using a variety of processing methods to produce desired end products. Thermochemical, biochemical, chemical, and bioconversion processes can convert lignocellulosic materials into bioenergy and biofertilizer. The isolation process of lignocellulosic materials into cellulose and nanocellulose includes pretreatment, ­chemo-​ ­mechanical, mechanical, chemical, liquefaction, and enzymatic processes. The properties of the produced cellulose and nanocellulose can be tailored to specific applications, such as biomaterials manufacturing, leather production, paper production, gels, biomedical applications, and bioadsorbent for wastewater treatment and animal waste. With the right processing technologies and improvements, the potential of bamboo is unlimited (­Lamaming et  al., 2022). Bamboo lignocellulosic biomass has a lot of potential as a fossil fuel substitute. Bamboo biomass can be converted in a variety of methods (­thermoelectric or biological conversion) to provide a variety of energy products (­charcoal, syngas, and biofuels) that can be used as alternatives to currently available fossil fuels. Comparing bamboo biomass to other renewable resources reveals that it has both benefits and limitations. Compared to other biomass feedstocks, it has improved fuel properties and is appropriate for both thermodynamic and biochemical routes. Bamboo biomass has limitations related to the establishment, logistics, and land occupation. If poorly managed, it can also have detrimental effects on the environment, so choosing bamboo as an ­energy-​­specific feedstock requires careful consideration to avoid or reduce any potential concerns. The energy requirements cannot be met entirely by biomass from bamboo. To fully realize

DOI: 10.1201/9781003358084-1

1

2

Cellulose

their potential and deliver a sustainable energy supply, they must be combined with other sources. ­Chapter 2 explored more on the suitability of bamboo biomass as an energy source as well as process of recovering energy in bamboo biomass. Oil palm is an essential crop commodity in Malaysia, and one of the world’s major manufacturers of items derived from oil palm. The ­by-​­products of oil palm trees include a wealth of biomass resources, which enables them to be put to a variety of further productive uses. These include the production of biodiesel, palm composite, pulp, and paper. Oil palm biomass is an intriguing option for high biorefinery production efficiency because of its high cellulose content. In order to successfully execute a circular economy over the long term, biorefineries are a necessary component. They must be created extensively and reclaimed as building blocks from items that have been converted because they are dependent on renewable resources. The utilization of lignocellulosic biomass as a feedstock results in significant value addition and is an essential component of a ­bio-​­based economy. The separation of the substrate specificity of biomass enables the production of distinct product flows that were previously conceivable. Even though biorefineries investigate biochemical, morphological, and physiological processes to perform fractionation, hydrolysis, and fermentation, the amount of fresh water that is used raises worries about the quality of the water as well as economic costs. In order for biorefineries to become financially and environmentally sustainable systems, it is vital for these facilities to implement technologies that make use of ­non-​­potable resources for biomass. In order to reduce the amount of fresh water needed, efforts are being undertaken to switch to using salt water instead. Therefore, C ­ hapter 3 delves into a comprehensive analysis of biorefineries that are supported by salt water, with an emphasis on the transformation of lignocellulosic biomass into biofuel and other ­value-​­added products. Production of biofuel from renewable resources has gained great attention as a potential candidate to replace fossil fuels partially or completely as transportation fuels. Due to its sugary structure, cellulose has the potential to be used for biofuel production, which requires the depolymerization and isolation of smaller sugar units that could then be transformed into fuel. Production of biofuels such as biogas, bioethanol, biodiesel, and biogas can be carried out through different pathways, namely biochemical and thermochemical. Currently, both technologies are commercially available for producing biofuel, and additional research and development are being conducted to reduce the delivered cost of biofuels. To ensure the feasibility of biofuel production, selecting the most suitable technology that is ­eco-​­friendly, has less energy consumption, and is ­cost-​­effective is among the issues that need consideration. Furthermore, the biofuel production process through biochemical and thermochemical pathways can also be influenced by the type of feedstock used for the processes. Thus, ­Chapter 4 presents the technologies involved in the production of biofuel through current thermochemical (­pyrolysis, gasification, and pyrolysis) and biochemical technologies. This chapter also describes the technological development of biofuels (­bioethanol, biobutanol, liquid fuel, solid biofuel, and syngas) from different types of feedstocks. Apart from an energy source, the enormous amount of biomass produced by the oil palm fields and mills, where it produces a large amount of lignocellulosic biomass such as oil palm trunks, oil palm fronds, EFB, p­ alm-​­pressed fibers, palm shells, and palm oil mill effluent (­POME), can be used as biofertilizer through composting. Composting is a widely adopted way to transform agricultural waste into organic fertilizer. This material contains a high concentration of cellulose, hemicellulose, and lignin, and its degradation affects composting efficiency (­Liu et al., 2022). The oil palm biomass also contains a high concentration of nutrients, and the nutrient composition could be used as biocompost and organic fertilizer, assisting in soil conditioning, and reducing the use of inorganic fertilizer in agriculture sectors while also reducing environmental impact. The high amount of biomass generated in oil palm fields and mills is a major concern because it leads to the bioconversion of biomass into fertilizer as part of their waste management strategy, which helps reduce waste discharge into rivers while restoring nutrients to the plant nutrition cycle. C ­ hapter 5 provides an extensive review of the latest updates on the conversion of different types of waste from the palm oil industry into fertilizer in Malaysia.

Introduction

3

The cellulose serves as the primary source of energy for the biological transformations, as well as the resulting temperature rise and chemical changes associated with composting (­Hubbe et al. 2010). The main carbon sources are cellulose and hemicellulose, which account for the majority of the carbon dioxide and heat. Cellulose degradation in the compost is important for providing carbon during the composting process. C ­ hapter 6 reviews recent research on the use of selected wastewater composting, with a focus on using wastewater content as a nutritional enhancer and moisturizer that can be used directly and recycled, as well as the possibility of reducing load in wastewater treatment plants. The wastewater from the industries of oil mills, olive mills, alcohol or molasses distilleries, swine, composting facilities, and monosodium glutamate are among those mentioned in the review. Cellulosic material used as bulking agents can help to reduce nitrogen loss during composting and achieve an appropriate C:N ratio. In the composting process, wastewater was incorporated, mixed, and absorbed by bulking agents such as green waste, grass clippings, mushroom waste, and rice husk into the formulation of wastewater composting, which was included to increase the compost porosity, which in turn enhanced the oxygen availability, which then accelerated the microbial activities. The wastewater can help accelerate the mineralization of organic matter by microorganisms. The wastewater and the bulking agents could provide better MC, adequate nutrients for microorganism growth, degrade the compost materials, and accelerate the rate of compost, thereby obtaining a good quality fertilizer as a final product. The increasing nutrients found in this effluent vary from 1.05% to 6.1% (­N), 0.06% to 2.8% (­P), and 0.06% to 12.43% (­K), proving their potential as nutrient enhancers. Cellulose fibers have relatively high strength, high stiffness, and low density. For a range of applications, biocomposites are gaining popularity as a more environmentally friendly alternative to synthetic composites. This is due to the increase in environmental awareness, especially in the issues of pollution and global warming, which has diverted researchers’ focus to e­ co-​­friendly biocomposites. Natural fibers such as hemp, kenaf, jute, and coir can be incorporated with ­bio-​­based polymers to form a composite. This natural ­fiber-​­reinforced composite (­biocomposite) has the potential to be used in different applications such as packaging, textiles, and various structural applications such as decking and paneling. Modern society is very interested in natural biocomposite materials because of their noble mechanical qualities, light density, superior life cycle, biodegradability, and cost efficiency. In ­Chapter 7, the background of biocomposites, their manufacturing process, properties, challenges, and the uses of biocomposites specifically as structural components in various applications, such as in automotive, building and construction, and the furniture industry, have been summarized. The key feature of a biocomposite in automotive applications is its lightweight material, which performs similar to conventional materials. Additionally, it also exhibits ­non-​­brittle fracture upon impact testing, which is one of the main requirements for automotive components. ­Chapter 8 discusses the fundamentals of natural fiber composites, its processing techniques, and the potential applications in the automotive sector, including the demands and future perspectives. The outcome from this chapter would benefit the researchers in this particular area as well as the industrial players in reducing waste disposal, greenhouse gas emissions, and life cycle considerations. As described in C ­ hapter 9, recently, the development of the construction industry has gone toward producing cement mortar that is high in strength and environmentally friendly. However, developing a cement mortar that is as strong as concrete is challenging because no coarse aggregate is used in the mortar mix. Thus, the development of new technologies and materials that can improve the strength of mortar without the use of coarse aggregates was studied. These days, additives to strengthen cement mortar by using natural resources have gained interest among researchers. Still, a limited study had been conducted to study the outcome of ­natural-​­based additives in cement mortar as a strengthening agent. This chapter deals with the importance of the utilization of cellulose nanocrystals (­CNCs) as a ­natural-​­based additive in cement mortar as a strengthening agent. The focus of this chapter is to identify important performance criteria and parameters of research that has been done and compare them with current research. This chapter then discusses the science and different

4

Cellulose

approaches to the utilization of CNCs and their ability to enhance the properties of materials. The differing performance of CNCs as admixture evaluation methods is discussed by looking at the different admixtures that each researcher reported. In ­Chapter 10, Tanpichai details the production of a­ ll-​­cellulose composites (­ACCs). The interfacial interaction between the cellulose particles and polymer matrix is a major concern for composite fabrication. ACCs have been prepared from various cellulose sources using impregnation or partial surface dissolution approaches with a specific solvent. These approaches can provide great interfacial adhesion between the reinforcement phase and polymer matrix that are both made from cellulose, affording promising improvements in the mechanical properties of ACCs compared with those of ­petroleum-​­based polymers and biopolymers. Herein, an overview of ACCs as well as factors that affect their physical properties (­such as transparency and crystallinity) and mechanical properties has been provided, as well as examples of the applications of ACCs. Nanocellulose is a strong reinforcement component in biocomposites, due to its enhanced dispersibility compared to microfibers and the tunability of its surface chemistry. ­Chapter 11 evaluates the potential of using the ­cellulose-​­based bioadhesives for wood, the application in ­wood-​­based composite. Polyhydroxyalkanoate (­PHA) can be used as feedstock for the production of thermoplastics and can be combined with other compounds to generate blends and composites, which is another one of its many strengths. Due to the green and biobased character of ­PHA-​­derived materials, their potential applications are vast. The PHAs can be blended with nanocellulose and other polymers as a matrix. The PHA could be produced using palm oil mill effluent (­POME). The POME is a thick, brownish liquid released from the palm oil mill during the oil extraction process. This liquid is highly enriched with organic contents, which need rigorous treatment before they can be released into the bodies of water. As the POME is released continuously, it provides the basis for its sustainable usage. POME could be valorized to produce the PHA. Ceasing the anaerobic treatment at the acidogenesis stage produces volatile fatty acids (­VFA), which would be the precursor for PHA synthesis. PHA such as polyhydroxybutyrate and poly(­­3-­​­­hydroxybutyrate-­​­­co-​­hydroxyvalerate) has been used to produce biodegradable plastic, but it is hampered by ­non-​­sustainable resources. Pure culture microorganisms such as Bacillus cereus, Cupriavidus necator, and mixed culture microorganisms have been utilized to store the PHA within its cellular structure by supplying the feedstock with an excess carbon source but limited nutrients. C ­ hapter 12 presented and discussed the characteristics of POME, the usage of bacterial strains to produce PHA, and the latest trend in the production of PHA from POME. Lignocellulosic material from agricultural waste is readily available and has great potential as a cheap and sustainable raw material for nanocellulose production. Nanosized cellulosic materials have received much attention due to their excellent properties, high strength, low cost, biodegradability, abundance, and renewable properties. The advantage of using nanosized cellulosic materials is not only because of these properties, but also due to their dimensions, at the nanometer scale, which opens many possible properties that have yet to be discovered. In principle, nanoscale cellulosic materials can be extracted from a variety of cellulosic sources, including plants, bacteria, algae, and animals, using various procedures. However, the main challenge is to find a process to obtain a higher yield of nanocellulose with efficient isolation from lignocellulosic sources. It is known that the combination of two or more treatment methods can increase the yield and rate of fibrillation as well as reduce energy consumption during processing. Appropriate isolation tech­ hapter 13 addresses the cellulose niques also promote the excellent properties of nanocellulose. C classification, a general overview of nanocellulose from various lignocellulosic sources, as well as the available factors in the extraction of nanocellulose, followed by introducing and comprehensively discussing various nanocellulose isolation techniques. Meanwhile, ­Chapter 14 details the isolation and properties of nanocellulose in the form of cellulose nanocrystals (­CNCs) derived from sugarcane bagasse. The chapter presented the yield and characteristics of CNC from bagasse, including the morphology and crystallinity index isolated from the various methods, including acid hydrolysis, catalyst TEMPO (­2,2,6,­6 -­​­­tetramethylpiperidin-­​­­1-​­oxy)

Introduction

5

oxidation, ultrasonication, and ­high-​­pressure homogenization. At 33% sulfuric acid concentration and 30 min hydrolysis time, the acid hydrolysis method produced the highest yield (­58%). The acid hydrolysis process yielded the highest crystallinity CNC (­89%), with a sulfuric acid concentration of 65% in 45 min. The morphology of CNC was observed by TEM analysis. The highest axial ratio was 64 with dimensions of 2 nm width and 255 nm length, which was obtained from acid hydrolysis using a concentration of 33% sulfuric acid and a hydrolysis time of 30 min. The yield, morphology, and crystallinity of CNC obtained by each method differ depending on the concentration of chemicals used, processing time, and mechanical treatment such as tools and pressure. Cellulose that has been liquefied becomes formable into gels that can be regenerated into complex structures and applications. In ­Chapter 15, regenerated cellulose in the forms of hydrogels, aerogels, cryogels, and xerogels has been thoroughly reviewed. The morphological structure, appearance, and properties of the regenerated cellulose products differ due to the preparation method, particularly how they are dried from the wet hydrogel. As a result, the various properties will lead to a variety of applications tailored to the fabricated products. This smart biopolymer has wide application in pharmaceutical and biomedical applications, particularly in wound care, therapeutics, cosmetology, cardiovascular diseases, oncology, ophthalmology, urology, drug delivery systems, tissue engineering, and tissue regeneration. It is thanks to their inherent physical, mechanical, and biological properties. In this regard, C ­ hapter 16 discussed and highlighted the recent development of ­nanocellulose-​­based hydrogel materials in the biomedical field, particularly in drug delivery, tissue engineering, wound dressing, and wound healing. Due to the extensive use of cellulose in the production of paper, the application of cellulose in paper production has seen a growth of over 3% CAGR through 2026. It helps shorten the paper’s drying period. It raises the printing quality and makes the paper better by making it less transparent and porous. Paper made from cellulose also takes less energy and raw materials. Cellulose will also provide lightweight, enhancing transportation energy efficiency (­Pulidindi and Prakash, 2022). ­Chapter  17 discusses the use of cellulose fiber in pulp and papermaking processes. The sources of cellulose, which cover various cellulose fiber sources including sources from wood, n­ on-​­wood, recycled fiber, and rags, were explained. The advantages and disadvantages of cellulose fiber derived from various sources and their suitability for producing many grades of paper products were also discussed. The following section covers the basic processes of cellulose fiber conversion into pulp before the papermaking process. This includes types of pulping methods, bleaching methods, and pulp blending processes. The beating process, the refining process, and details on additives used in papermaking were described under the pulp blending subtopic. The basic processes involved in papermaking processes, such as forming, dewatering, pressing, drying, calendaring, reeling, and winding, were included. These basic processes were described based on the basic processes of the Fourdrinier machine. Meanwhile, the last section covers the papermaking processes used with the cellulose ­fiber-​­based pulp before it is sent to customers for further application in ­paper-​­based products. The harvesting and processing of allium generate various waste streams. Allium peels as a raw material for papermaking are an innovative solution to global environmental problems such as deforestation and global warming. Allium peels contain cellulose and hemicellulose with low lignin content compared to commercial pulp materials such as hardwood and canola straw. However, allium peels alone cannot serve as a sole substitute to produce ­good-​­quality paper, as the technology of papermaking using allium peels is still in the development stage. As a result, ­Chapter 18 gives an overview of the current state of development of Allium peels as a papermaking pulp. In addition, the challenges and prospects of allium pulp for papermaking are also presented. Leather has a significant impact on the world economy. The use of cellulose in the production of leather was covered in ­Chapter 19. Leather manufacturing involves a chemical process applied to a biological matrix that uses a huge quantity of chemicals and generates large amounts of residue. Cellulose, a sustainable and renewable product, can be used during leather production in three different steps: tanning, retanning, and finishing. In tanning, cellulose helps the penetration of metals

6

Cellulose

into the hide matrix, contributing to the fibers’ stability and improving the tanning performance. In retanning, the use of cellulose improved the physical and aesthetic properties of leather. In leather finishing, cellulose was mixed with other chemicals to obtain better leather, without compromising its aesthetic properties. During the process of adjusting the thickness of the leather or lowering it, solid waste is generated. Cellulose can be added to these wastes to obtain v­ alue-​­added products. They are used in different areas, such as agriculture and packaging. ­Chapter 20 provides an overview of the utilization of cellulose as a main material for wastewater treatment. Because of their abundance of natural polymers and their promising combination of efficiency, low cost, and chemical freedom, c­ ellulose-​­based materials have been used in wastewater treatment. Depending on the cellulose type and wastewater type, cellulose absorbent can be manufactured in powder or granule form, as fine particles, in fiber form, as gel, as a film, or in membrane form. Furthermore, the discussion in this chapter focused on the various types of cellulose modification and the most common effluent removal method using modified cellulose. The challenge and concern of using cellulose in wastewater treatment are also among the aspects highlighted in this chapter. The demand for biodegradable cat litter adsorbent is increasing due to increased awareness of environmental and health impacts among cat owners and cat lovers. The use of clay and bentonite could be harmful to the environment if not properly managed. The EFB produced by oil palm industries have the potential to be developed into cat litter adsorbents. The hydrophilic functional groups of cellulose, hemicellulose, and lignin in the EFB structure allow it to absorb water. Furthermore, cellulose shares a structure and ion exchange with organic materials such as resin, both of which are suitable as absorbents (­Saueprasearsit et al., 2010). ­Chapter 21 studies the comparison of imported cat litter with locally produced EFB pellets for performance. Four types of biodegradable cat litter, namely pine, EFB pellet, dried tofu, and a mixture of EFB pellet and pine (­4:1), were evaluated for their physical properties, water absorption, and odor. The length and diameter of the samples varied due to the production specifications, but in terms of bulk density, dried tofu had the highest density, followed by EFB pellets. The pH of the samples was mostly in the neutral range, except for the dried tofu, which had an acidic value of 4.53. The sensory odor test showed that dried tofu caused better adsorption of the softener odor, as it was barely perceived by the respondents, followed by wood and EFB pellets. The EFB p­ ellet-​­wood sample, on the other hand, was easier to smell when tested. In summary, EFB pellets have comparable characteristics to imported cat litter, which is advantageous as it is locally produced. ­Chapter 22 presents some of the challenges and future perspectives of the ­cellulose-​­based products that have been encountered and some recommendations. As a versatile material, cellulose offers more research areas that can be explored in parallel with the advancement of technology that can offer sustainable products.

REFERENCES Hubbe, M.A., Nazhad, M.,  & Sanchez, C. (­2010). Composting as a way to convert cellulosic biomass and organic waste into high-​­value soil amendments: A review. Bioresources, 5(­4), 2808–​­2854. Lamaming, J., Saalah, S., Rajin, M., Ismail, N.M., & Yaser, A.Z. (­2022). A review on bamboo based adsorbent for removal of contaminants in wastewater. International Journal of Chemical Engineering, 4, 1–​­14. Liu, Q., He, X., Luo, G., Wang, K., & Li, D. (­2022). Deciphering the dominant components and functions of bacterial communities for lignocellulose degradation at the composting thermophilic phase. Bioresource Technology, 348, 126808. Pulidindi, K. & Prakash, A. (­2022). Cellulose Market. Global Market Insights. Accessed on 25 October 2022 at https://­www.gminsights.com/­industry-​­analysis/­cellulose-​­market. Saueprasearsit, P., Nuanjarae, M., & Chinlapa, M. (­2010). Biosorption of lead (­Pb2+) by Luffa cylindrical fibre. Environmental Research Journal, 4(­1), 157–​­166.

2

A Brief Overview of the Use of Bamboo Biomass in the Asian Region’s Energy Production Siti Ayu Aziz and Mohd Sani Sarjadi Universiti Malaysia Sabah

CONTENTS Introduction.........................................................................................................................................7 The Benefits of Bamboo as a Potential Source of Biomass................................................................9 An Analysis of the Viability of Bamboo Biomass as a Source of Energy........................................ 10 In Comparison with Other Forms of Renewable Energy.................................................................. 12 Emissions of Greenhouse Gases.................................................................................................. 13 Water Consumption...................................................................................................................... 13 Accessibility................................................................................................................................. 14 Land Usage.................................................................................................................................. 14 Restriction Imposed by Technology............................................................................................. 15 In Comparison with other Forms of Energy Crops...................................................................... 15 Methods for Extracting Energy from Bamboo’s Biomass................................................................ 15 Thermochemical Conversion....................................................................................................... 16 Pyrolysis.................................................................................................................................. 16 Gasification.............................................................................................................................. 16 Direct Combustion.................................................................................................................. 18 Biochemical Conversion.............................................................................................................. 19 The Present Situation Regarding the Use of Bamboo Biomass for the Generation of Energy.........20 Malaysia....................................................................................................................................... 21 Indonesia...................................................................................................................................... 22 Thailand....................................................................................................................................... 22 Vietnam........................................................................................................................................ 23 Japan.............................................................................................................................................24 Conclusion........................................................................................................................................24 References.........................................................................................................................................24

INTRODUCTION Cellulose makes up between 30% and 50% of lignocellulosic biomass, whereas hemicellulose makes up between 25% and 35%, and lignin accounts for between 5% and 30% of this type of biomass. An appealing feedstock for the production of fuel alcohol is lignocellulosic biomass, which includes sources such as agricultural waste residues, wood, grass, forestry, and municipal solid wastes. This is because lignocellulosic biomass sources are abundant, and their costs are relatively cheap (­Roque et al., 2012). The breakdown of cellulose into monomeric sugars and the oligosaccharides cellotetraose, cellotriose, and cellobiose results in the creation of biomass. Cellulose is the primary

DOI: 10.1201/9781003358084-2

7

8

Cellulose

component of all biomass (­glucose and fructose). Hemicellulose is the second most common type of polymer found in biomass, and it is the polymer that is responsible for the formation of pentoses (­xylose and arabinose) and hexoses (­galactose, glucose, and mannose). Sugars found in hemicellulose have a lower molecular weight than those found in cellulose, and they are distinguished by having short helical chains that are easily hydrolyzed (­Agbor et al., 2011). The modification of the cellulose structure, with the end goal of increasing its availability to enzymes and/­or chemicals, is the primary objective of the ­pre-​­treatment of lignocellulosic biomass (­Holm and Lassi, 2011). Biorefineries are conducting extensive research into lignocellulosic biomass resources, such as bamboo, as potential replacements for the generation of industrial fuels that are derived from fossil fuels (­Wang et al., 2020). The majority of the lignocellulose in bamboo species is composed of cellulose (­38%–​­50%), hemicellulose (­23%–​­32%), and lignin (­15%–​­25%) (­Zhang et al., 2021). The quantities of lignin found in woody and herbaceous plants are very different from one another in terms of their respective chemical makeup. Lignin content ranges from 8% to 15% in herbaceous plants to approximately 20%–​­38% in woody plant species (­­Poveda-​­Giraldo et  al., 2021). Despite being a species of herb, bamboo has a high lignin content that is equivalent to that of woody plants despite its herbaceous nature (­Jianfei et al., 2020). These components are generated by the process of photosynthesis, which makes use of carbon dioxide from the atmosphere (­Wang et al., 2021). Cellulose has emerged as a critical component for use in biorefineries over the past few years (­Kumar and Verma, 2021). During the subsequent fermentation stage, which involves a great variety of microbial species, the glucose that was produced as a ­by-​­product of the hydrolysis of cellulose in a biorefinery is converted into a variety of white compounds. These substances have the potential to take the place of those that are produced by oil refineries (­Islam et al., 2020). The utilization of lignocellulosic biomass results in the production of bioethanol, which is then sold on the market (­Patel and Shah, 2021). Bioethanol is a w ­ ell-​­known product of biorefineries. The production of greenhouse gases like carbon dioxide can be reduced thanks to the usage of bioethanol, which has the potential to lessen the severity of the adverse effects of climate change (­Safieddin et al., 2020). Fuels for transportation that are created from petroleum can be replaced by bioethanol, which can also replace these fuels. However, the cost of producing bioethanol using present technologies from lignocellulosic biomass is not yet comparable with the cost of producing gasoline (­refining oil) (­Adewuyi, 2020). Bamboo is the common name given to members of the Bambusoideae subfamily of the Andropogoneae/­Poaceae family of grasses. This taxonomic group of gigantic woody grasses is known as the Bambusoideae. There are 1,250 species of bamboo, the majority of which are relatively ­fast-​­growing and can achieve stand maturity in 5 years or less (­Scurlock et al., 2008). Bamboos are classified into 75 different genera, and there are a total of 75 different genera. The tropics are where bamboos are most commonly found; however, they can be found growing naturally on every continent, both in tropical and temperate climates. Asia has a total land area of more than 180,000 km and is home to around 1,000 different species. A significant portion of this land is made up of natural stands of native species rather than plantations or introduced species. On its own, China is home to more than 300 species, which are organized into 44 genera and spread across 33,000 km2 (­about 3% of the country’s total forest land). Another country that produces a lot of bamboo is India, which has 130 different kinds and occupies 96,000 km2 (­or roughly 13% of the total wooded area). Other countries besides China and Japan that use bamboo extensively in their construction include Bangladesh, Indonesia, and Thailand. Bamboo is native to regions that range from subtropical to temperate, with the exception of Europe. Since the beginning of human history, bamboo has been cultivated and utilized by people in a variety of contexts. Building material can be derived from the bamboo stem because of its qualities of being strong, lightweight, and flexible. From the fibers of bamboo, products such as paper, textiles, and boards can be made. Bamboo shoots of many different types are a popular source of nutrition in many Asian countries. In recent years, in an effort to find alternative energy sources to replace dwindling supplies of fossil fuels, a new method of harnessing bamboo’s potential as a

9

A Brief Overview of the Use of Bamboo Biomass

­TABLE 2.1 Bamboo Biomass Pilot Plant Locations in Malaysia, Indonesia, Vietnam, and Japan Country

Location

Malaysia Indonesia

Gurun, Kedah Mentawai, West Sumatera Nankan town, Kumamoto Lam Dong

Japan Vietnam

Technology

Capacity (­kW)

Gasification Gasification

4,000 700

2022 2018

Pakar (­2020) CPI (­2021)

Cogeneration

995 (­power) 6,795 (­thermal) Not available

2023

Nakanishi (­2019)

Not available

Launch Date

Not available

References

Truong and Le (­2014)

source of energy has been added to a list. The biomass of bamboo is used as a raw material for the production of other kinds of energy, such as electricity and biofuels. Bamboo is a perennial plant that may thrive in climates ranging from tropical to subtropical to more temperate. In common parlance, bamboo is referred to be the “­poor man’s tree,” but in recent years, it has gained popularity as an innovative, modern, and inexpensive material that can serve as a substitute for wood. According to Scurlock et al. (­2008), India is the second most prosperous country in Asia in terms of bamboo genetic resources. China is the most prosperous country in this regard. The countries that come together to form the ASEAN region have only recently started to grasp the potential for the development of biomass energy from bamboo’s resources. ­Table 2.1 provides an overview of the current initiatives being developed to create biomass bamboo pilot plants in the countries of Malaysia, Indonesia, Vietnam, and Japan.

THE BENEFITS OF BAMBOO AS A POTENTIAL SOURCE OF BIOMASS As a result of the quickening pace of economic development in these nations, bamboo has emerged as a significant biomass resource around the world over the past few decades (­Scurlock et al., 2008). In addition to its usage in traditional forms of energy and a variety of other uses, bamboo biomass has more recently been reinvented to make use of gasification for the purpose of electric valorization (­Kerlero and de Bussy, 2012). In addition, the incorporation of bamboo into volunteer carbon payment systems has contributed to an increase in its desirability as a plantation species. In recent years, similar developments have led to an increase in the number of bamboo plantations in Thailand. Despite the fact that specific knowledge with biomass production and energy and alternative utilization possibilities is still limited, these plantations have been able to flourish. According to Scurlock et al. (­2008), bamboo is most likely to flourish in a climate that is warm and humid (­with an annual average temperature of 15°­C–​­20°C and yearly precipitation of 1,­000–​ ­1,500 mm). On three different continents, including Asia, Africa, and South America, there exist wild bamboo forests as well as planted bamboo forests. It was estimated that more than 36 million hectares were covered with bamboo forests around the world. The monsoon region of East Asia, specifically India and China, has the highest incidence of the disease worldwide (­11.4 and 5.4 million ha, respectively). As shown in ­Figure  2.1, the total area covered by bamboo in Asia has increased by 10% over the course of the past 15 years (­Lobovikov et al., 2007). This increase is mostly attributable to the massive planting of bamboo in China and India. Based on data by Lobovikov et al. (­2007), the inventory of the world’s bamboo resources can be found in ­Table 2.2. Bamboo has a high potential to serve as a bioresource for lignocellulosic biomasses for a number of different reasons. These reasons include its rapid clonal growth, which results in the accumulation of abundant lignocellulosic biomasses in a short period of time (­He et al., 2013; Ma et al., 2018), high fiber contents (­Das et al., 2005), lack of agricultural land requirement, more extended harvest

10

Cellulose

India 31%

Others 41%

Vietnam 2% Myanmar 2%

­FIGURE 2.1 

China 15% Ecuador 4%

Indonesia 5%

Countries with the most abundant supply of bamboo.

­TABLE 2.2 Bamboo Forest Area ­Bamboo-​­Covered Land Area (­1,000 ha) Region Africa Latin America Asia Total

2005

2000

1990

 2,758 10,399 23,620 36,777

 2,758 10,399 22,499 35,656

 2,758 -​­ 21,230 23,988

period, and the existence of a large, yet underutilized genetic pool (­Das et al., 2008). In addition, they have the appropriate features for use as a fuel, such as a high caloric value, low levels of ash, chlorine, and moisture content, and a lowered temperature at which ash is formed (­Engler et al., 2012; Fang and Jia, 2012). Cellulose, hemicellulose, and lignin are the primary structural components in plants that take up carbon (­Tang et al., 2017). As a consequence of this, LCBs obtained from bamboo provide a significant potential as a biomass stock for the conversion of energy in a number of Asian countries, including Malaysia (­Chin et al., 2017), Indonesia (­Engler et al., 2012), India (­Sharma et al., 2018; Singh et al., 2017; Hauchhum and Singson, 2019), and China (­Biswal et al., 2021). ­Table 2.3 provides information on the fuel qualities of a number of different bamboo species (­Scurlock et al., 2008; Singh et al., 2017).

AN ANALYSIS OF THE VIABILITY OF BAMBOO BIOMASS AS A SOURCE OF ENERGY In comparison with conventional fossil fuels, traditional fossil fuels, such as oil and products derived from oil refineries, natural gas, and coal, are used extensively because they possess several desirable qualities in fuel, including the fact that they are very stable and produce a significant amount of energy, as well as the fact that they are very convenient, as shown in T ­ able 2.4 (­Scurlock et al., 2008; Singh et  al., 2017). Other traditional fossil fuels, such as natural gas and products derived from natural gas refineries, are also used extensively. Fossil fuels are a potential contender for usage as portable forms of energy due to the ease with which they may be utilized, stored, and carried. They

11

A Brief Overview of the Use of Bamboo Biomass

­TABLE 2.3 Fuel Properties of Certain Species of Bamboo Bamboo Properties Species of Bamboo

Higher Heating Value (­kJ/­kg)

Volatile Matter (%)

Ash (%)

Fixed Carbon (%)

Moisture (%)

Bambusa beecheyana Dendrocalamus asper Phyllostachys nigra Phyllostachys bambusoides Phyllostachys bissetii

15.700 17.585 19.27 19.49

63.10 71.70 72.27 75.55

3.70 2.70 0.41 0.53

18.90 19.80 13.7 14.38

14.30 5.80 13.62 9.54

19.51

64.99

0.9

12.14

21.97

­TABLE 2.4 Comparison of the Thermal Conductivity of Bamboo Biomass versus Fossil Fuels Fuel Bamboo biomass (­Phyllostachys bissetii) Natural gas Coal Gasoline

Reduced Thermal Conductivity (­MJ/­kg)

Increased Thermal Conductivity (­MJ/­kg)

N/­A

19.51

47.141 22.732 43.448

52.225 23.968 46.536

are the form of fuel that is most easily combustible in comparison with other types of fuel, such as biofuel or wood fuel, due to the fact that they contain a high concentration of energy. As a consequence of this, a substantial amount of energy is produced by them. Fossil fuels have the highest calorific value and are therefore the most efficient source for the production of energy (­Astier, 2013). Because biomass has a poorer thermal conductivity and a higher water content, a greater volume or mass of the material is required to produce the same amount of energy. This is due to the fact that biomass contains more water. The storing and transporting of biomass will be made more difficult as a direct result of this factor. In addition, the grade of the fossil fuels that may be taken from each of the different sites is, for the most part, comparable. However, there can be a large amount of variation in both the quality of biomass and biofuels. It is challenging to produce biofuel from biomass that is compatible with modern engines due to the fact that these engines were built to run only on fossil fuel. When we switch to biofuel, either these engines will need to be redesigned from the ground up or the quality of the fuel itself will need to be improved in order for it to satisfy the requirements. In today’s culture, however, the use of fossil fuels raises a few questions and concerns. The production of energy from these sources has two major drawbacks: First, there is a finite amount of resources available, and second, there is an increase in pollution due to the burning of fossil fuels. Fossil fuels are n­ on-​­renewable sources, which means that they are unable to replace themselves, and the rate at which they are being depleted is extremely concerning. In 40 years, it is projected that global oil production will reach its highest point, signaling the beginning of a gradual fall in oil production. It is anticipated that coal production will not begin for another 220 years, while natural gas production will not begin for another 60 years (­Poppens et  al., 2013). Because there are less and fewer fossil fuels available, their prices will continue to rise indefinitely. In addition to this, they are responsible for the emission of a sizeable quantity of carbon dioxide (­CO2) into the

12

Cellulose

atmosphere, which is a crucial component of both global warming and climate change. This quantity of carbon dioxide was taken up by ancient plants over a period of millions of years; however, it is now being added to the atmosphere over a period of time that is significantly shorter. There is a good chance that the world will not react and adjust quickly to such a massive upheaval. Because of the destructive impacts it has, the environment and all living things, including people, will be negatively impacted. As a direct result of these issues, a rising number of individuals are looking for alternative energy sources to minimize our reliance on fossil fuels, and biomass is increasingly being regarded as a viable choice among these alternatives. Because bamboo biomass can be burned almost instantly when it is in its dry state, it is an excellent choice for cooking and heating in rural areas and among people with poor incomes. In order to turn biomass into electricity, the cogeneration facility has been designed specifically for that purpose. It is possible to process biomass in a variety of ways, which can result in the production of char, flammable gas, and biofuel. All three of these products have properties that are comparable to those of fossil fuel. In the ­not-­​­­too-​­distant future, biomass will likely be able to completely supplant fossil fuel as an essential component of the worldwide energy grid. When compared to fossil fuels, biomass has several significant advantages, the most important of which are its sustainability and its lower carbon dioxide emissions. Bamboo is a source of renewable energy, which means that the biomass it produces may be replaced at a rate that is compatible with its use as an extraction resource. Carbon dioxide is released during the processing of biomass, which includes both thermal conversion and biochemical conversion (­CO2). On the other hand, this does not contribute in any way to an increase in the concentration of greenhouse gases in the atmosphere. The carbon dioxide that is released as a result of these actions is the same type of carbon dioxide that is fixed into the atmosphere by bamboo plants during the process of photosynthesis. Another aspect that needs to be mentioned is the cost of the product. At the moment, the price of electricity generated from biomass is lower than the price of power generated from fossil fuels. However, in the future there will be a shift because there won’t be enough fossil fuels. When this occurs, the transition will take place naturally, and the cost of fuel derived from biomass will be lower than that of fossil fuel. The criteria were compiled and compared in ­Table 2.5, which compared bamboo biomass to fossil fuel (­Nakanishi, 2019; Truong and Le, 2014).

IN COMPARISON WITH OTHER FORMS OF RENEWABLE ENERGY Hydropower, wind power, and solar power are some of the other forms of renewable energy that are readily available in addition to biomass. Since the dawn of time, people have been harnessing

­TABLE 2.5 Summary of the Properties of Fossil Fuels and Biomass Criteria Accessibility Generated energy (­per same mass) Logistic (­storage and transportation) Quality Sustainability CO2 emission

Bamboo Biomass

Fossil Fuel

Must plant and harvest after a ­3-​­to ­4-​­year time frame Significantly smaller

Drawn straight from an existing resource and used immediately Much bigger

More complicated (­need more prominent space for transportation and storage) Diverge Source of renewable energy Not raise CO2 concentrations in the atmosphere

Transportable and storable Incorporated ­Non-​­renewable source Increase CO2 levels in the atmosphere

13

A Brief Overview of the Use of Bamboo Biomass

­TABLE 2.6 Comparison of the Efficiencies of Various Power Generation Methods Technology Biomass Wind Hydro Photovoltaic

Range of Efficiency (%) ­16–​­43 ­23–​­45 1,000°C Produce syngas High pressure conversion reaction for feedstock with high moisture content Conversion of high moisture feedstock under supercritical condition.

the desired type of fuel, the environmental standards, the economic conditions, and the various reaction parameter condition (­Canabarro et al., 2013). Different approaches were found to be able to produce different types of biofuels (­­Table 4.2). Typically, a combination of liquid, solid, and gas can be produced from the conversion of feedstock via pyrolysis. In addition, conversion of organic materials using liquefaction produces crude ­bio-​­oil which can be further purified to produce other chemicals such as alcohol, dimethyl ether, and methyl alcohol (­Zhang et al., 2019), while biosynthetic gas that consists of carbon dioxide, carbon monoxide, hydrogen, and methane can be produced via gasification reaction. The direct combustion of feedstock is one of the dominant thermochemical conversion pathways globally (­Tanger et al., 2013).

Pyrolysis Pyrolysis is a direct thermal conversion which involves decomposition of organic material at temperature range of 300°­C–​­800°C in the absence of oxygen (­Chowdhury et al., 2017). A variety of products such as solid, liquids, and gases can be generated from this thermal process (­­Figure 4.4). The pyrolysis process is a complex process that manipulation of the reaction process could significantly influence the final product. In the pyrolysis process, it involves several major steps including drying,

Biorefinery of Biofuel Production

49

­FIGURE 4.4  Type of pyrolysis and it products.

devolatilization, and char formation process. The thermal decomposition of organic materials starts at a temperature of 300°­C–​­500°C. During this stage, the chain of carbon, oxygen, and hydrogen in the materials breaks down into smaller molecules to form gases and condensable vapors, and formation of solid charcoal can be obtained at the end of the pyrolysis. The charcoal yield decreases as the temperature increases. The yield of products resulting from biomass pyrolysis can be maximized as follows: charcoal (­a low temperature, low heating rate process), liquid products (­a low temperature, high heating rate, short gas residence time process), and fuel gas (­a high temperature, low heating rate, long gas residence time process) (­Mohan et al., 2006, Balat et al., 2009, Abella et al., 2007). According to Tanger et al. (­2013), pyrolysis at high temperature and longer residence time favors then gas production, whereas reaction at moderate temperatures ranging 400°­C– ​­600°C and short residence reaction are suitable to generate more liquid. In contrast, pyrolysis reaction at lower temperature and longer residence times is optimum for production of solid products (­Williams and Besler, 1996). The pyrolysis reaction at different condition not only affect the products, but also influence the chemical composition distribution such as alcohol, ketone, aldehyde, ester, phenolic compounds, and heterocyclic derivatives (­Lyu et al., 2015, Sarkar and Wang, 2020, Ben et al., 2019). The pyrolysis reaction for bioenergy from biomass could also be divided into three different reactions, namely catalytic, fast, and flash. Generally, the difference between those reactions is the process condition which is mainly contributed by residence time, heating rate, and temperature. The details of each pyrolysis reaction are discussed later.

Slow Pyrolysis Slow pyrolysis is one of the thermal decomposition processes that is conducted at low temperature and low heating rate. This pyrolysis process is commonly used to produce h­ igh-​­quality and reliable char from various feedstocks. The temperature range for this reaction is typically between 300°C and 700°C, with heating rate of 1°­C–​­30°C/­min (­Ronsse et  al., 2013, Noor et  al., 2019). Several studies on the slow pyrolysis process on various feedstocks have been reported in the literature. For example, pyrolysis of cellulose, Lemna minor, rice straw (­RS), pine, and microalgae such as

50

Cellulose

Chlorella pyrenoidosa has been reported in the literature. According to Wang et al. (­2019), their study on pyrolysis of six different feedstocks reported that pyrolysis products mainly gas, solid, and ­bio-​­oil can be influenced by the ­hydrogen-­​­­to-​­carbon ratio available in the feedstock. Another study on slow pyrolysis of mixture biomass and plastic in ­fixed-​­bed reactor also indicated that ­co-​­pyrolysis could positively affect the final product generated from the process. The study also indicated that difference on the feedstock structural characteristic plays important role in the production of char and ­bio-​­oil yield (­Çepelioğullar and Pütün, 2014). The study showed that the biochar produced from the pyrolysis of different feedstocks such as cotton stalk, hazelnut shells, sunflower residues, and Euphorbia rigida were 28.01%, 30.10%, 21.69%, and 23.12%, respectively. However, slow pyrolysis process exhibited technological limitation particularly on the quality of ­bio-​­oil produced from the reaction. Moreover, low heating transfer for long residence time was found to have contributed to the extra energy input to produce desired final products (­Bridgwater et al., 1999, Hilal DemirbaŞ, 2005).

Fast Pyrolysis Fast pyrolysis is a thermal reaction of either organic or inorganic materials that commonly conducted at moderate temperature between 450°C and 600°C with rapid heating rates of more than 100°C/­min. This thermal reaction generally occurs at short residence time and produces high yield of ­good-​­quality ­bio-​­oil with a minimum char and gas of 12% and 13%, respectively. The ­high-​ ­quality ­bio-​­oil produced from fast pyrolysis potentially substitutes fuel oil in electricity application. Fast pyrolysis of various feedstocks such as woody materials, agricultural residues, aquatic biomass, and microalgae for b­ io-​­oil production has been reported (­Morgan et al., 2016, Muradov et al., 2010, Wang et al., 2013, ­Thangalazhy-​­Gopakumar and Adhikari, 2016). Most of the studies indicate that the ­bio-​­oil production from various feedstocks is significantly influenced by the type of feedstock. The main operational conditions including temperature, gas flow rate, residence time, and feedstock particle size are among the parameters that have been reported and play important role on ­bio-​­oil yield production via fast pyrolysis in fluidized bed reactor (­Jahirul et al., 2012). According to Onay (­2007), their study of b­ io-​­oil production via fast pyrolysis of safflower seeds indicated that maximum b­ io-​­oil yield of 54% was obtained for pyrolysis at 600°C. Another study on the fast pyrolysis of manure sample pyrolyzed at 600°C, 800°C, and 1000°C indicated that maximum ­bio-​­oil production of 27% was achieved for the pyrolysis at 800°C (­­Fernandez-​­Lopez et al., 2017). Similar b­ io-​­oil trend has also been reported by Sukiran et al. (­2016) in their investigation of fast pyrolysis of EFB, which concluded that high ­bio-​­oil yield was obtained when the pyrolysis was conducted at 500°C. The study also indicated that particle size of feedstock could play crucial role in ­bio-​­oil yield. Fast pyrolysis of EFB in fluidized reactor indicated that maximum ­bio-​­oil was observed for the pyrolysis reaction using ­126–​­150 μ. Low ­bio-​­oil produced from pyrolysis using small particle size could be explained by the fact that small particle size will lead to ­un-​­uniform heating process, thus resulting to low pyrolysis yield (­Encinar et al., 2000, Seebauer et al., 1997). The changes of pyrolysis operational condition not only influence the b­ io-​­oil yield, but could also affect the quality of ­bio-​­oil produced. According to the previous characterization of ­bio-​­oil from feedstock, it is indicated that the common chemical compounds present are hydrocarbon, fatty acid, alcohol, ester, ether, ketone, and phenolic compound (­Chukwuneke et al., 2019, Morgan et al., 2015). Furthermore, hydrogen, carbon, and oxygen ration are among the important indicators for the future potential of ­bio-​­oil application. It was found that ­bio-​­oil from pyrolysis of anaerobic sludge at high temperature contains high ­hydrogen-­​­­to-​­carbon ratio and ­oxygen-­​­­to-​­carbon ratio (­K im et al., 2012). Another study on fast pyrolysis of chestnut capsule contains low oxygen content with ­hydrogen-­​­­to-​­carbon ratio which is close to conventional fuel gas (­Kar and Keles, 2013). ­Bio-​­oil with high oxygen content is highly reactive, is unstable, and is not suitable for use as fuel application due to storage limitation. Thus, due to this problem, further upgrading is required to improve the storage stability.

Biorefinery of Biofuel Production

51

Flash Pyrolysis Another type of pyrolysis reaction is flash pyrolysis that involves rapid heating rate >1000°C/­s at high temperature between 900°C and 1300°C. Similar to other pyrolysis reaction, the main product generated from the flash pyrolysis is b­ io-​­oil. Generally, the reaction rate for this pyrolysis is less than 0.5 s. Many investigations on flash pyrolysis of various feedstocks have reported a promising approach to produce ­high-​­quality ­bio-​­oil. Flash pyrolysis of wood fibers obtained maximum conversion with 60% liquid yield at reaction temperature range between 450°C and 550°C at residence time less than 4 s (­Imran et al., 2016). The study also reported that flash pyrolysis at longer residence time could be negatively impacted by increasing the ­bio-​­oil product. Another study by Urban et al. (­2017) on pyrolysis of milled soybean at temperature range 250°­C–​­610°C using 0.2 and 0.3 s reaction produced nearly 70% of ­bio-​­oil with low gas and tar residue. This study concludes that high liquid produced from the flash pyrolysis could be attributed to low secondary reaction of oil produced due to short retention time. Another study on the flash pyrolysis of mixed wood also indicated that maximum ­bio-​­oil yield of 67% with high polycyclic aromatic hydrocarbon was obtained at high temperature more than 550°C (­Horne and Williams, 1996). Further increase of temperature was found to slightly reduce ­bio-​­oil yield. Similar study has been observed on the flash pyrolysis of other types of feedstocks such as corn stalk, and wheat straw in heated laminar entrained reactor (­Shuangning et al., 2005). Although many studies have demonstrated the potential of producing b­ io-​­oil from a variety of feedstocks, this technology has some limitations, such as poor thermal stability, low viscosity and high oxygenate compounds, necessitating more ­in-​­depth investigation into ­bio-​­oil upgrading and reactor design to further improve the process.

Pyrolysis Technology Several pyrolysis technologies such as microwave pyrolysis, plasma pyrolysis, and vacuum pyrolysis have been introduced to improve production of ­bio-​­oil and biochar from biomass. Development of new pyrolysis technology makes the thermal conversion process become more rapid, selective, and efficient compared to the conventional pyrolysis system. ­Microwave-​­assisted pyrolysis process is among new technology that has been introduced to improve pyrolysis process. The main differences of this technology compared to the conventional approach lies on the type of heating method. Fundamentally, conventional pyrolysis involves transfer of thermal energy from the surface of biomass into the depth of feedstock and partially combusts to produce ­bio-​­oil, ­hydrocarbon-​­rich gas, and c­ arbon-​­rich biochar, whereas the microwave pyrolysis involves transfer of electromagnetic energy into inside the biomass and constantly accumulates inside the biomass. High energy accumulation at the core of biomass causes temperature gradient from inside to outside of the biomass and release volatile compounds of the feedstock from inside core to the biomass surface (­Zhang et al., 2017). Microwave pyrolysis poses more advantages including selective, rapid, uniformly internal heating of biomass and flexible over conventional pyrolysis process (­Xie et al., 2015). Investigation on the microwave pyrolysis toward different lignocellulose biomass feedstocks has been conducted for b­ io-​­oil and biochar production. For instance, this microwave pyrolysis was used to convert RS to produce biochar at low temperature for CO2 absorbent application. The study indicated that production of biochar from RS using microwave pyrolysis could reduce reaction time, cost, and energy consumption (­Huang et al., 2015). Another investigation on the microwave pyrolysis of coconut shell for ­bio-​­oil production has also been reported. Study by Nuryana et al. (­2020) indicated that ­bio-​­oil from coconut shell produced from microwave pyrolysis contained high phenolic compound which exhibits growth of E. coli. This indicated that the product generated from this pyrolysis process could be used as antibacterial agent. Furthermore, a microwave pyrolysis

52

Cellulose

with the presence of catalyst has also been developed to improve the pyrolysis process. Microwave pyrolysis of sewage sludge showed that the presence of catalyst H ­ ZSM-​­5 could reduce pyrolysis temperature, and maximum ­bio-​­oil was observed when the pyrolysis reaction was performed at 550°C (­Xie et al., 2014). Although this microwave pyrolysis exhibits great potential as future thermal conversion technology, it is obvious that processing at large scale is a big challenge in comparison with conventional pyrolysis technology. Currently, several efforts involving s­ caling-​­up of microwave pyrolysis can be made by both academic institutes and industrial companies, especially involving local safety and environmental issue.

Vacuum Pyrolysis Vacuum pyrolysis is another technology that could be the future potential for thermal conversion of biomass. This technology involves pyrolysis reaction under ­sub-​­atmospheric pressure within the reactor. The low pressure occurring in the system makes the carbon conversion to become more efficient and avoids side reaction occurring during the process. This pyrolysis has also been reported, is able to reduce decomposition temperature, and shortens organic vapor residence time (­Luda, 2012). Investigation of the products generated from vacuum pyrolysis on different biomass feedstocks such as wood (­­Garcìa-​­Pérez et al., 2007), pine sawdust (­Zhang et al., 2010), coffee residue (­Chen et al., 2017), and palm kernel cake (­Dewayanto et al., 2013) has been reported by many researchers. To date, most of the studies are performed at the bench scale level. Most of the studies indicated that ­bio-​­oil is the dominant product produced from vacuum pyrolysis. A study by Chen et al. (­2017) on the vacuum pyrolysis of coffee residue indicated that ­bio-​­oil was the highest product with 42.29% followed by biochar and gas with 33.14% and 24.57%, respectively. Similar study has also been reported on the vacuum pyrolysis of lignocellulosic biomass such as forest pinewood waste, which indicated that b­ io-​­oil represents 70% of the final product produced followed by biochar and gas (­Amutio et al., 2011). Investigation on the pyrolysis product from different biomass feedstocks such as softwood and hardwood rich in fiber also found that the main product produced from this process is ­bio-​­oil followed by biochar (­­Garcìa-​­Pérez et al., 2007). The potential application of the ­bio-​­oil and biochar derived from vacuum pyrolysis of biomass has also been investigated by several researchers. For instance, characterization of ­bio-​­oil produced from vacuum pyrolysis of soft back biomass contains low Na+K+Ca with low viscosity, and high net energy can be used to operate gas turbine (­Boucher et al., 2000). In addition, another study on the characterization of ­wood-​­derived ­bio-​­oil produced via vacuum pyrolysis that contains low oxygen level can be potentially used for future liquid fuel (­Özbay and Özçifçi, 2021). Furthermore, biochar produced from waste palm shell (­WPS) through vacuum pyrolysis can be potentially used as substrate for oyster mushroom (­Pleurotus ostreatus) cultivation (­Kaźmierczak et al., 2017). It was found that ­WPS-​­derived biochar contains high porous structure and BET surface area that could exhibit high absorption properties as biofertilizer. This type of biochar could also enhance and stimulate the growth of microbes and targeted plant.

Plasma Pyrolysis Plasma pyrolysis technology is an emerging thermal conversion technology that could provide complete solution for solid waste management including lignocellulosic materials. This technology involves disintegration of carbonaceous material into new compound fragments under limited oxygen environment. Plasma pyrolysis uses high energy from burning of working gas such as argon (­Ar), helium (­He), hydrogen (­H2), and nitrogen (­N2), and provides extremely high temperature to decompose feedstock materials via chemical reaction including decomposition, evaporation, pyrolysis, and oxidation. The conversion of biomass occurred in a plasma reactor zone that contained active electron, ion, and excited molecules with high energy radiation. Exposure of biomass in this

Biorefinery of Biofuel Production

53

area will rapidly decompose, and volatile matter is released from the biomass. In general, the final products produced from this technology are mainly CO, H2, and n­ on-​­leachable solid hydrocarbons. There are four different plasma generators that are commonly being developed for plasma pyrolysis including direct current, alternate current, radio frequency (­R F) plasma pyrolysis, and microwave plasma pyrolysis. Numerous investigations on plasma pyrolysis for valorization of biomass into other ­value-​­added products were carried out. A study by Tu et al. (­2009) indicated that application of RF plasma pyrolysis was able to produce higher ­hydrocarbon-​­rich solid product compared to gas from RS. The study indicated that the formation of pyrolysis product is significantly influenced by reaction temperature, and the suitable temperature to obtain high solid fraction from RS was obtained at 740 K. Another study on similar feedstock reported that plasma pyrolysis using ­pilot-​ ­scale plasma torch thermolysis reactor indicated that almost 90% of the RS was converted into ­CO-​­ and H2-​­rich gas product (­­Je-​­Lueng et al. 2010). Similar study on pyrolysis of glycerol and crushed wood using water steam plasma pyrolysis reactor also found that higher synthesis gas was obtained when the reaction was conducted in the presence of steam (­Tamošiūnas et al., 2016). This clearly indicated that that moisture content of the feedstock could significantly affect the pyrolysis product and gas composition obtained from the process. A study by Dermawan et al. (­2022) (­seed waste into ­high-​­efficiency biochar by atmospheric pressure microwave plasma) indicated that biochar obtained from the microwave plasma pyrolysis of RS and golden shower has a great potential to be used for bioremediation application. Biochar produced from this pyrolysis exhibited higher methylene blue absorption capacity compared to that produced from conventional pyrolysis approach. The study indicated that high surface area and high pore volume were observed from both biochar of RS and GS pyrolyzed using microwave plasma pyrolysis technology.

Hydrothermal Liquefaction Conversion of h­ igh-­​­­moisture-​­content feedstock for biofuel production such as microalgae, sludge, and animal waste is one of the problems in this area. Processing of wet feedstock requires a lot of energy for drying process prior to be subjected for biofuel production via thermal conversion process. Liquefaction has been introduced to be applied to overcome this limitation. Liquefaction is considered as a promising conversion process to convert biomass that is presence of water or organic solvent in the presence or without catalyst into liquid biofuel. The liquefaction is commonly conducted under high temperature in hot liquid water, and biocrude produced has a complex mixture of ketone, phenols, alcohol, aldehydes, and carboxylic acid (­Shuangning et al., 2005, Reddy et al., 2016). Analysis of HL on various feedstocks has been reported and showed that the quality of the biocrude produced is depending on the chemical composition distribution in the feedstock. Comparative analysis on biocrude production from various bark species via liquefaction showed that biocrude quality, chemical composition, and conversion efficiency varied significantly with type of feedstock (­Feng et al., 2014). In addition, another study by Karagoz et al. (­2005) investigated the influence of feedstock types on biocrude production via liquefaction and indicated that cellulose showed the highest conversion compared to sawdust and rice husk. Another study on hydrothermal of forest and agricultural feedstock indicated that agricultural biomass such as wheat straw and sugarcane exhibited high conversion under thermal and catalytic reaction conditions compared to forest biomass (­Singh et al., 2015). The biocrude yield obtained from hydrothermal reaction could also be contributed by the operational conditions. Numerous studies have reported that alteration of hydrothermal liquefaction condition could affect the biocrude yield and chemical distribution in the b­ io-​­oil (­Guo et al., 2015). The operational conditions such as reaction temperature, residence time, and ­solvent-­​­­to-​­feedstock ratios are among the parameters that play crucial role in conversion of biomass feedstock to biocrude via hydrothermal liquefaction. Studies by Wei and Jie (­2018) evaluated the interaction of liquefaction parameters on biocrude production from microalgae Spirulina sp. indicated that the maximum biocrude production of 41.5% was obtained when the reaction was conducted at temperature 357°C for

54

Cellulose

37 min with reaction condition of 10.5%. Their study also reported that operational parameters such as temperature and feedstock ratio exhibited the most influential factor on the biocrude production process. Mathanker et al. (­2020) conducted the liquefaction of corn stover at different temperatures of 250°C, 300°C, 350°C, and 375°C which indicated that the maximum biocrude was observed for the liquefaction at 300°C. Further increase of temperature resulted in low biocrude production due to the hydrocracking of hydrochar and biocrude generated from the process. Similar observation has also been reported on the hydrothermal liquefaction of barley straw (­Zhu et al., 2015), oil palm empty fruit bunches (­EFBs), palm mesocarp fiber, and palm kernel shell. Motavaf and Savage (­2021) investigation on the biocrude oil production from food waste indicated that further increase of pressure from 10.2 to 16.9 MPa could enhance 20% of biocrude yield. In another study on liquefaction of palm frond biomass at different pressure, it was found that this parameter could be influenced by solvent used during the process (­Prasetyo et al., 2020). The study indicated that the pressure of the solvent can be predicted according to its boiling temperature. The study suggested that the utilization of solvent with low boiling point should obtain maximum biocrude oil yield at low temperature.

Gasification Gasification is another thermal conversion pathway that has received attention recently (­Canabarro et al., 2013, Verma et al., 2012). In this process, the feedstock is converted to a simplified biosynthetic gas or syngas that consists of carbon monoxide (­CO), hydrogen (­H2), carbon dioxide (­CO2), NOx, SOX, tar, and slag (­Sikarwar et al., 2017). Typically, the gasification reaction is performed at temperature of >800°C under optimized oxygen or water (­H2O). Usually, the gasification involved a complex reaction of organic feedstock including drying, pyrolysis, combustion, cracking oxidation, and reduction which can be carried out via following reaction (­­Figure 4.5).

­FIGURE 4.5 

Gasification of feedstock reaction process.

Biorefinery of Biofuel Production

55

Gasification Parameters Syngas formed from gasification of biomass varies depending on the type of feedstock and reaction conditions such as particle size, pressure, and temperature. Effect of Feedstock Types Selection of the suitable feedstock is not considerable for better quality syngas. Previous study indicated that different biomass feedstocks used in gasification can directly link to the chemical composition of syngas (­­Table 4.3). Most of the suitable reported that the syngas yield is related to the chemical composition between cellulose and hemicellulose content in the feedstock, while the residues generated are correlated with the lignin content. Numerous investigations on gasification of different feedstocks employed significantly affect the thermal decomposition kinetics, reactivity, gas composition, and its calorific value (­Matsumoto et al., 2009). Effect of Temperature Another factor that could affect the gasification reaction is temperature that will influence the syngas production yield, quality, ash, and tar that related to problem in the conversion process. Typically, the gasification of biomass feedstock is performed at temperature ranging between 400°­C–​­1000°C. The gasification temperature can be classified into three ranges, namely low (­400°­C– ​­600°C), median (­600°­C–​­900°C), and high temperatures (­beyond 1000°C). Studies on the gasification temperature on various feedstocks including bamboo (­Wongsiriamnuay et al., 2013), switch grass pellet (­Madadian et al., 2017), microalgae (­Raheem et al., 2017), and olive bagasse (­Almeida et  al., 2019) have been reported elsewhere. Most of the investigations indicated that increase of gasification temperature will result into increase in the proportion of H2, CO, carbon conversion, and gas yield. It is expected that gasification at higher temperature will affect the several reaction rates during the process. According to Sadhwani et  al. (­2016), the increase of temperature reaction from 800°C to 950°C will lead to increase the syngas production yield from southern pine biomass. The study also indicated that gasification reaction at different temperatures could significantly affect the syngas composition. Further increase of gasification temperature was found to increase CO and H2 concentration. Similar observation was reported on the air gasification of microalgal biomass Chlorella vulgaris (­Raheem et al., 2017). The study reported that temperature was the most important factor that influences overall gasification of microalgal biomass sample. The maximum syngas yield was observed for the gasification conducted at 950°C, corresponding to 20% for the gasification at 700°­C–​­950°C. A similar observation has also been reported on the influence of temperature on different types of feedstock such as switchgrass, cardboard, and hardwood (­Madadian et al., 2017).

­FISCHER–​­TROPSCH CATALYTIC REACTION The syngas produced from gasification can be further converted into wide range of chemicals and fuel via F ­ ischer–​­Tropsch (­FT) reaction synthesis. Several types of chemicals such as methanol, ethanol, hydrocarbon, and oxygenate chemicals can be produced through this reaction. In general, this FT is a complex chemical reaction of hydrogen and carbon monoxide into liquid chemical that typically occurs at high temperatures of 150°­C–​­350°C and pressure with the presence of metal catalyst. The FT reaction can be written as follows:

nCO + ( 2n + 1) H 2 → CnH ( 2n + 2 ) + nH 2O

where CnH (­2n + 2) represents a range of hydrocarbons, ranging from ­low-­​­­molecular-​­weight gases (­n = 1, methane), by way of gasoline (­n = ­5–​­12), diesel fuel (­n  = ­13–​­17), and as far as solid waxes (­n > 17).

Rice husk EFB Palm trunk Wood pellet Kenaf Eucalyptus Pine

CO

14.9 16.6 20.97 29.8 33.1 24.2 14.18

CO2 12.9 19.2 13.19 7.9 63.1 9.7 16.35

2.3 4.3 3.65 50.9 1.7 2.1 2.94

CH4 ND ND ND ND ND ND ND

C2H2 ND ND ND ND ND ND ND

C2H4

Note: HHV, high heating value; LHV, low heating value; ND, not detected.

H2

13.6 5.6 15.09 32.1 2.0 22.5 10

Feedstock

Dry Gas Composition (%)

­TABLE 4.3 Syngas Production From Various Feedstocks

ND ND ND ND ND ND ND

C2H6 4.26 5.9 ND ND ND 8.08 ­ HV-​­5.32 L

HHV/­LHV (­MJ/­kg)

References Yoon et al. (­2012) Lahijani and Zainal (­2011) Jalil et al. (­2011) Raibhole and Sapali (­2012) Hasanoğlu et al. (­2019) Borges et al. (­2019) Abdoulmoumine et al. (­2014)

56 Cellulose

Biorefinery of Biofuel Production

57

The hydrocarbons produced by FT process can be refined and used in place of more conventional liquid fuels derived from crude oil. Synthetic fuel can be produced by a variety of gasification methods, with ­gas-­​­­to-​­liquid, ­coal-­​­­to-​­liquid, and ­biomass-­​­­to-​­liquid being the most widespread. Syngas produced from gasification process that contains tars, particulate, and contaminants needs to be clean prior to be subjected for FT synthesis reaction. This cleaning process is required because the presence of these contaminants will cause poison and clog at the downstream process stage. The cleaning process can be carried out either through chemical or through physical methods. To date, physical cleaning method through several techniques such as cyclone and filter is considered the most suitable technique to remove particulate or tars when this technique is economically feasible. Production of liquid fuel and hydrocarbon from syngas can be influenced by several factors including temperature, pressure, and the presence of catalyst. Reaction pressure and different H2/­ CO ratios are among the most important operating parameters that could affect final FT reaction synthesis products. Study by Sauciuc et  al. (­2012) on their FT synthesis of biomass at different pressures ranging from 16 to 24 bar indicated that maximum CO conversion was achieved when the reaction was conducted at 24 bar. In addition, most study on FT reaction from gasification of different biomasses indicated that the hydrocarbon produced is significantly affected by temperature reaction (­Pendyala et al., 2014, Farias et al., 2007, Zamani et al., 2016). In general, the FT synthesis is conducted at temperature range of 180°­C–​­350°C depending on the pressure and catalyst presence in the reaction. Studies indicated that increase of reaction temperature will increase the reaction rate ­non-​­linearly. According to Farias et al. (­2007), it is indicated that the maximum hydrocarbon and liquid fuel selectivity can be observed for reaction that performed at low temperature 240°C. The study indicated that this temperature was favorable to produce liquid fuel from syngas. Maximum hydrocarbon can also be achieved by introducing the suitable metal catalyst. Several studies have reported that catalysts such as ­Fe-​­Mn, Rh/­SiO2, ­Cu-​­ZnO/­Al2O3, Rg/­­MCM-​­41, Cu/­­MCM-​­41, and ­Cu-­​­­Fe-​­K/­­MCM-​­41 are among the common catalysts used to produce liquid fuel from syngas via FT synthesis (­­Okoye-​­Chine et al., 2022, ­Valero-​­Romero et al., 2021). Selecting the suitable catalyst is important to achieve maximum selectivity, in which the catalyst properties may affect the interaction, active site, surface hydrophobicity, and performance during the FT synthesis reaction.

BIOCHEMICAL CONVERSION Besides thermochemical reactions, biochemical conversion is considered an environmentally friendly method, which involves the utilization of bacteria, microorganisms, and enzymes to break down biomass into liquid fuels and gases such as bioethanol, biobutanol, and biogas. The good yield and quality of the liquid fuels and gases could be used to replace ­non-​­renewable sources of fossil fuels (­Yusoff et al., 2020). Generally, several steps are involved in the biochemical conversion of biomass into liquid biofuel or gas production, including biomass pretreatment, hydrolysis, and fermentation (­­Figure 4.6).

Pretreatment The main purpose of biomass pretreatment is to disrupt the natural recalcitrance carbohydrate lignin that is located at the outer membrane of the biomass, which could limit the accessibility of enzymes to cellulose and hemicelluloses (­Cheah et al., 2020). The choice of the pretreatment types is very crucial, since this could directly affect the rate of hydrolysis and quality and of the liquid fuels and gases production (­Aftab et al., 2019). Therefore, a successful pretreatment method must be taken into consideration in terms of the sugar released and solid loading concentration in conjunction with the overall pretreatment process, biomass feedstock, enzymes, or organisms to be applied. Generally, the pretreatment of the biomass can be categorized into physical, chemical, and biological. We have emphasized the different types of pretreatment methods toward the different types

58

­FIGURE 4.6 

Cellulose

The formation of ­value-​­added products from lignocellulosic biomass.

of lignocellulosic biomasses, aiming to remove the recalcitrance lignin while releasing the cellulose and hemicellulose components for bioconversion into liquid biofuels (­Kumar and Sharma, 2017). Physical Pretreatment Physical pretreatment is a common pretreatment that involves the breakdown of the outer recalcitrance membrane surrounding the lignocellulose biomass into fermentable sugars. This pretreatment method typically involves the reduction of the lignocellulose biomass size and crystallinity through increasing the temperature and pressure toward the biomass. The energy required for physical pretreatment toward the lignocellulose biomass is dependent on the final particle size and the reduction in the crystallinity of the lignocellulosic material (­Brodeur et al., 2011). Hence, this reduction could improve the mass transfer characteristic from the reduction in the biomass particle size, while also improving the hydrolysis results (­Maurya et al., 2015). Physical pretreatments such as milling, extrusion, ultrasound, microwave irradiation, and grinding could be applied on lignocellulosic biomass prior to the hydrolysis process (­Ariffin et al., 2008). The biomass was exposed to a high temperature of 300°C, followed by mixing and shearing. This softens the biomass fibers. The feasibility of the physical pretreatment was in agreement with a previous study, which demonstrates that the milling pretreatment on barely strew could obtain a glucose concentration of up to 7 g/­L during the hydrolysis process, which was economically feasible for bioethanol production (­Raud et al., 2020). Apart from that, Marta et al. (­2020) also offered an ultrasonic pretreatment on the mixture of Sida hermaphrodita (­L.) Rusby mixed with cattle manure which could enhance the production of biogas. El Achkar et al. (­2018) also proved that ultrasonic pretreatment could enhance biomethane production using a sonication frequency of 50 kHz, a temperature of less than 25°C, and a residence time of 4­ 0–​­70 min. In order to achieve an effective lignocellulosic biomass pretreatment process, the combination of physical pretreatment with other technologies can be empirically explored. Chemical Pretreatment Chemical pretreatment is the most popular method on a commercial scale, which has been extensively applied for cellulosic delignification in the pulping industry (­Baruah et al., 2018). Chemicals that are commonly applied toward the lignocellulosic biomass pretreatment are acid and alkali. Generally, sulfuric acid, nitric acid, phosphoric acid, and hydrochloric acid are common acids typically used for acid pretreatment. This acid pretreatment technology can be conducted under concentrated or diluted acid toward the lignocellulosic biomass. However, using concentrated acid is less popular, is attributable to the inhibitory compound formation, and has negative impact on

Biorefinery of Biofuel Production

59

the environment (­Maurya et al., 2015). Therefore, Baruah et al. performed diluted acid pretreatment ( 0.2) (­Malik et al., 2018). It also contains nutrients including nitrogen (­up to 4.2 g/­L), potassium (­up to 17.5 g/­L), and phosphorus (­up to 3.0 g/­L) (­Hoarau et al., 2018). This characteristic depends on the raw materials used for producing the alcohol.

Wastewater as Nutrient Enhancer and Moisturizer for Compost Production

87

Swine waste is a type of highly concentrated organic waste that contains a high concentration of carbon, nitrogen, phosphorus, and other elements (­Karakashev et al., 2008). According to Fan et al. (­2019a), every 10,000 pigs breeding in pig farms produces 190 tons of livestock breeding waste per day, with approximately 40% solid manure and 60% SW/­LM with an average MC of 75%, causing major environmental disturbances such as water and soil pollution and pollutants into the atmosphere (­Bustamante et al., 2013; Dennehy et al., 2017). Organic contaminants, ammonia nitrogen, and other substances that may be addressed biochemically are common in livestock and poultry breeding wastewaters. The TL is produced by ­bio-​­trickling filters, which is used for the removal of NH3 in composting site facilities. Following l­ong-​­term operation, the accumulation of ­nitrogen-​­containing compounds and nitrogen species in the TL may have detrimental effects on nitrifying bacteria and reduce bioreactor efficiency. The nitrogen (­NH3–​­N) in the smells was then preserved in the TL wastewater, which contains a variety of inorganic nitrogen. As a flavor enhancer, monosodium glutamate (­MSG) is extensively used in food products throughout East and Southeast Asia. MSG production in China accounts for about half of the world’s total output (­Liu and Zhou, 2010). After extraction of MSG from fermentation liquor, the residual dark brown wastewater and effluent have high concentrations of COD, NH3–​­N, sulfate, and a strong acidity (­Yang et al., 2005; Ji et al., 2014). MSGW has a very low pH and is full of proteins, amino acids, sulfate, and total organic carbon, as well as being free of heavy metal pollution (­Bai et al., 2004). It also doesn’t have any heavy metal pollution.

NUTRIENT ENHANCER AND MOISTURIZER IN COMPOSTING POME In spite of the fact that no chemicals are applied during the oil extraction process, POME is considered ­non-​­toxic, yet it has been identified as a major source of aquatic pollution due to the fact that it depletes dissolved oxygen when dumped untreated into water bodies. However, it also contains significant amounts of nitrogen, phosphorus, potassium, magnesium, and calcium (­Rupani et al., 2010), all of which are essential nutrients for plant growth. Because of its ­non-​­toxic nature and fertilizing characteristics, POME can be utilized as a nutrient enhancer substitute in the sense of providing the mineral requirements of the plant’s growing environment and acting as a moisturizer. Moisture loss is attributed to the evaporation of water due to high ambient temperatures and turning during the composting process. Addition of POME can replenish the compost pile and overcome water loss, so that the microbial activity can be sustained (­Baharuddin et al., 2009). In POME composting, using a combination of other materials as a bulking agent can further improve the performance of the final compost. Oil palm decanter cake (­OPDC), paper, grass clippings, and manures are among the additives that can be used as a source of nitrogen or carbon source and an offset to higher moisture content during composting (­Barthod et al., 2018). A few reports have been using POME for composting in the recent years (­­Table  6.2). The application of POME helps in accelerating the mineralization of organic matter by microorganisms (­Kala et al., 2009). Ahmad et al. (­2014) investigated the ­co-​­composting of POME and ­chipped-​­ground oil palm frond (­OPF). The use of POME served as a microbial source and maintained the moisture content at around 55%–​­65%, which led to a good aeration for bioactivity of the microorganism. The final compost contains 0.1% (­P) and 0.9% (­K), has a moisture content of 61%, has a pH of 8.1, and has a C/­N ratio of 24. The study found that ­co-​­composting of OPF and POME produced a compost with an acceptable value of C/­N and nutrients. However, the critical nutrients were found to be lower compared to compost made from empty fruit bunches (­EFBs) (­Baharuddin et al., 2009; Ahmad et al., 2016). This attributed to the low nutrient levels found in the raw OPF (­0.85% N, 0.05% P, and 1.73% K) as compared to raw EFB (­1.2% N, 0.08%, and 1.73% K).

88

Cellulose

­TABLE 6.2 Industrial Wastewater as Nutrient Enhancer and Moisturizer in Production of Compost in Recent Years by Several Works Type of Wastewater (%)

Solid Substrate (­s) (%)

POME (­75)

EFB (­25)

POME (­67)

­Chipped-​­ground oil palm frond (­33)

Palm oil mill effluent (­POME) (­71)

EFB (­24) Decanter cake (­5)

AnPOME (­23)

Paper (­31), grass clippings (­46)

POME (­6)

EFB (­63), recycled compost (­31) EFB

POME OMW (­58)

Grape marc (­14), green waste (­14), OMS (­14)

OMW (­50)

Grape marc (­25), Green waste (­25)

OMW (­50)

Grape marc (­50)

Olive mill wastewater (­60)

Municipal green waste (­40)

OMW (­67)

Household waste (­33)

OMW (­75)

Cotton residue (­25)

Composting Conditions

Final Compost Performance

­Microbes–​­Composting Time (­­50–​­60  days), turning C/­N (­17), pH (­7.8), MC (­80%), (­once in 3 days), pH (­5), GI (­80%) C/­N (­17), pH (­8.1), MC (­61%), Time (­60  days), C/­N (­24), N (­1.2 %), P (­0.1%), K (­0.9%) turning (­Every 3 days), pH (­7.0), Tmax (­56°C) Time (­70  days), C/­N (­24), C/­N (­24), pH (­8.4), MC (­60%), turning (­3 times in 14 days), N (­1.57%), P (­0.21%), K size (­EFB, ­150–​­200  mm), (­0.65%) pH (­8.0), Tmax (­38°C) Time (­40 days), C/­N (­33), pH C/­N (­31), pH (­7.2), MC (­53%), N (­1.2%), P (­0.1%), K (­0.4%), (­7.0), Tmax (­31°C) GI (­158%) Time (­43  days), C/­N (­39), C/­N (­13), MC (­59%) Tmax (­55°C) N (­2.86%) Time (­40  days), C/­N (­25, C/­N (­14), pH (­8), OM loss 35,45), Tmax (­60°C) (­74%) Time (­98  days), C/­N (­34), pH (­7.0), (­MC (­30%), EC (­1.75 turning (­once every 3 days at mS/­cm), beginning, then every P (­0.09%), K (­0.28) GI (­100%) 7 days, finally once every 15 days), pH (­8.5), Tmax (­68°C) Time (­100  days), C/­N (­34), C/­N (­12), pH (­8.3), MC (­55%), turning (­once every 3 days at EC (­1.92 mS/­cm), P (­346 beginning, then every mg/­kg), K (­226 mg/­kg), GI 7 days, finally once every (­90%) 15 days), pH (­6.5), Tmax (­68°C) Time (­90  days), C/­N (­23), pH (­8.6), MC (­55%), EC (­5.1 turning (­every 14 days), pH mS/­cm), N (­35.3 g/­kg), P (­8.6), Tmax (­60°C) (­12.1 g/­kg), K (­64.4 g/­kg), GI (­156%) Time (­140  days), C/­N (­21.5), C/­N (­21.5), pH (­8.2), MC Size (­municipal green (­50%), N (­1.05%), P (­0.14%), waste ≤ 30 mm), pH K (­0.79%) (­5.8), Temp (­55°C) Time (­150  days), C/­N (­35), C/­N (­10), pH (­7.5), MC (­43%), turning (­once in 7 days), pH N (­3.49%), P (­0.32%), GI (­6.4), Tmax (­60°C) (­94%) Time (­130  days), C/­N (­18), MC (­59%), N (­3.8 %), GI turning (­64th day), pH (­7.3), (­90%) Tmax (­30°C)

References

Mohammad et al. (­2013) Ahmad et al. (­2014) Adam et al. (­2016)

Zahrim et al. (­2016) Alkarimiah and Suja (­2020) Hasan et al. (­2021) Majbar et al. (­2017)

Majbar et al. (­2018)

Galliou et al. (­2018)

Avidov et al. (­2018)

Atif et al. (­2020) Kefalogianni et al. (­2021) (Continued)

89

Wastewater as Nutrient Enhancer and Moisturizer for Compost Production

­TABLE 6.2 (Continued) Industrial Wastewater as Nutrient Enhancer and Moisturizer in Production of Compost in Recent Years by Several Works Type of Wastewater (%) Alcohol/­ molasses distillery wastewater (­DSW) (­80) SW (­8.97  L)

Solid Substrate (­s) (%)

Composting Conditions

Final Compost Performance

References

Pressmud (­20)

Time (­40  days), C/­N (­34), turning (­daily), pH (­7.8), Tmax (­64°C)

pH (­6.8), EC (­1.22 dS/­m), N (­2.0%), P (­1.8%), K (­3.3%), GI (­92%)

Malik et al. (­2019)

Solid pig manure (­83.3), Rice husk (­16.7)

Time (­30 days), turning (­every 2 days during thermophilic stage & every ­5–​­10  days during other stages), pH (­7.3), Tmax (­64°C) Time (­30 days), C/­N (­23 and turning (­every 2 days during thermophilic stage & every ­5–​­10  days during other stages), pH (­7.3), Tmax (­64°C and 69°C)

MC (­41%), N (­2.11%), P (­2.63%), K (­1.67%), GI (­82%)

Fan et al. (­2021)

Corncob: pH (­8.0), EC (­2.71 mS/­cm), N (­36.5 g/­kg), P (­29.8 g/­kg), K (­201.1 g/­kg), GI (­81%) Rice husk: pH (­7.3), EC (­3.13 mS/­cm), N (­24.4 g/­kg), P (­28.2 g/­kg), K (­19.8 g/­kg), GI (­83%) C/­N (­15), pH (­7.7), MC (­38%), N (­6.1%), GI (­79%)

Fan et al. (­2019a)

SW (­50)

Solid pig manure (­83.3), Rice husk (­R) (­16.7), Corncob (­C) (­16.7)

Composting TL (­nd)

Mushroom bran (­43), ­pre-​ ­consumer food wastes (­43), and ­post-​­consumer food wastes (­14)

­Nitrate-​­rich STL (­67)

Fermentation residue (­17), sawdust (­10), food waste (­3), mushroom brans (­3) Fermentation residue (­17), sawdust (­10), food waste (­3), mushroom brans (­3) Fermentation residue (­17), sawdust (­10), mushroom (­3), food waste (­3)

­Ammonium-​ r­ ich STL (­67)

­Nitrite-​­rich STL (­67)

Time (­15 days), aeration rate (­0.002  m3/­min), C/­N (­36), turning (­every 3 days), size (­mushroom bran 90%), and excellent adhesion performance (­tissue shear stress of 54.2 kPa) • ­pH-​­responsive drug release behavior • Excellent biocompatibility and antioxidant effect • In vitro and in vivo results revealed excellent antibacterial effects, skin tissue regeneration, and wound closure capabilities • Sufficient mechanical strength, swelling ability, water retention, and oxygen transmission Jiang et al. (­2022) rate • Hydrogels exhibited efficient bactericidal effects and no toxic effects on normal human epithelial cells • In vitro release showed that the hydrogel system could release menthol stably over a long period of time • The performance of the hydrogel formulation with a 7% addition of Zn(­NO3)­2⋅6H2O is the most suitable for wound healing applications • Hydrogels contained a porous ­three-​­dimensional reticulum structure and had high Song et al (­2021) mechanical properties • Hydrogels possessed outstanding antibacterial properties and good biocompatibility • Effectively repaired wound defects in mice models and wound healing reached 97.89% within 15 days

Findings

­TABLE 16.2 (Continued) Some Examples of Research on N ­ anocellulose-​­Based Hydrogels for Biomedical Applications in recent years

Developments and Applications of NC-Based Hydrogels 247

248

Cellulose

Many studies had been done on NC ­hydrogel-​­based strain sensors. Heidarian et al. (­2022) produced a hydrogel by imine formation of carboxyl methyl chitosan, oxidized cellulose nanofibers, and chitin nanofibers followed by two subsequent ­cross-​­linking stages which are immersion in tannic acid solution to create hydrogen bonds and soaking in Fe(­III) solution to give electrical conductivity property to the hydrogel. Meanwhile, Zheng et al. (­2019) prepared strain sensors with a combination of CNFs and graphene (­GN) ­co-​­incorporated poly(­vinyl alcohol)-​­borax (­­GN-​­CNF@PVA) hydrogel. CNFs act as a ­bio-​­template and dispersant to support GN to create a homogeneous ­GN–​­CNF aqueous dispersion, increasing the mechanical flexibility and strength while providing good conductivity. Results showed high stretchability, excellent viscoelasticity with storage modulus up to 3.7 kPa, rapid ­self-​ ­healing ability of 20 s, and high healing efficiency of around 97.7% (­­Table 16.2).

CONCLUSION Cellulose has become an interesting material for various applications due to its high mechanical strength, biocompatibility, biodegradability, and ­eco-​­friendliness. NC as hydrogels, either from native cellulose or derivatives of cellulose, appears to be an exciting and attractive material, not only in the biomedical fields but also in other applications and future applications. In terms of advanced technology and engineering progress, there is still room for more discoveries and fundamental knowledge in ­cellulose-​­based research fields. For example, 3D bioprinting technology, ­super-​­hydrophobic membranes, and superabsorbents are some of the many emerging and growing fields that will benefit many industries. Many significant works on the use of ­cellulose-​­based materials together with their related technologies have been demonstrated and reported. In applying the products beyond the laboratory scale, comprehensive and systematic studies are still needed to enable ­high-​­throughput production.

REFERENCES Abeer, M.M., Mohd Amin, M.C.I.,  & Martin, C. (­2014). A review of bacterial cellulose-​­based drug delivery systems: Their biochemistry, current approaches and future prospects. Journal of Pharmacy and Pharmacology, 66(­8), 1047–​­1061. Acharya, S., Abidi, N., Rajbhandari, R., & Meulewaeter, F. (­2014). Chemical cationization of cotton fabric for improved dye uptake. Cellulose, 21(­6), 4693–​­4706. Acharya, S., Hu, Y., & Abidi, N. (­2021). Cellulose dissolution in ionic liquid under mild conditions: Effect of a hydrolysis and temperature. Fibers, 9(­1), 5. Almeida, A.P., Saraiva, J.N., Cavaco, G., Portela, R.P., Leal, C.R., Sobral, R.G.,  & Almeida, P.L. (­2022). Crosslinked bacterial cellulose hydrogels for biomedical applications. European Polymer Journal, 177, 111438. Alven, S., Aderibigbe, B.A. (­ 2020). Chitosan and cellulose-​­ based hydrogels for wound management. International Journal of Molecule Science, 21, 1–​­30. Aravamudhan, A., Ramos, D.M., Nada, A.A.,  & Kumbar, S.G. (­2014). Natural polymers: Polysaccharides and their derivatives for biomedical applications. In Kumbar, S.G., Laurencin, C.T., & Deng, M. (­eds) Natural and Synthetic Biomedical Polymers (­­pp. 67–​­89). Elsevier, Amsterdam. Athukoralalage, S.S., Balu, R., Dutta, N.K., & Choudhury, N.R. (­2019). 3D bioprinted nanocellulose-​­based hydrogels for tissue engineering applications: A brief review. Polymers, 11, 898. Baghaei, B., & Skrifvars, M. (­2020). All-​­cellulose composites: A review of recent studies on structure, properties and applications. Molecules, 25(­12), 2836. Butylina, S., Geng, S., & Oksman, K. (­2016). Properties of as-​­prepared and freeze-​­dried hydrogels made from poly (­vinyl alcohol) and cellulose nanocrystals using freeze-​­thaw technique. European Polymer Journal, 81, 386–​­396. Chamkouri, H., & Mahyodin Chamkouri, M. (­2021). A review of hydrogels, their properties and applications in medicine. American Journal of Biomedical Science & Research, 11(­6), 485–​­493. Chen, L., Hong, F., Yang, X.X., & Han, S.F. (­2013). Biotransformation of wheat straw to bacterial cellulose and its mechanism. Bioresource Technology, 135, 464–​­468.

Developments and Applications of NC-Based Hydrogels

249

Cheng, K.C., Huang, C.F., Wei, Y.,  & Hsu, S.H. (­2019). Novel chitosan–​­cellulose nanofiber selfhealing hydrogels to correlate self-​­healing properties of hydrogels with neural regeneration effects. NPG Asia Materials, 11(­25), 1–​­17. Chu, S., Maples, M. M., & Bryant, S. J. (­2020). Cell encapsulation spatially alters crosslink density of poly (­ethylene glycol) hydrogels formed from free-​­radical polymerizations. Acta Biomaterialia, 109, 37–​­50. Ciolacu, D., & Popa, V.I. (­2020). Nanocelluloses: Preparations, properties, and applications in medicine. In Popa, V.I. (­Ed.), Pulp Production and Processing (­2nd ed., ­pp. 317–​­340). Walter de Gruyter, Berlin. Ciolacu, D., Rudaz, C., Vasilescu, M., & Budtova, T. (­2016). Physically and chemically cross-​­linked cellulose cryogels: Structure, properties and application for controlled release. Carbohydrate Polymers, 151, 392–​­400. Ciolacu, D. E., & Suflet, D.M. (­2018). Cellulose-​­based hydrogels for medical/­pharmaceutical applications. In Popa, V., & Volf, I. (­ed) Biomass as Renewable Raw Material to Obtain Bioproducts of ­High-​­Tech Value (­­pp. 401–​­439). Elsevier, Amsterdam. Čolić, M., Mihajlović, D., Mathew, A., Naseri, N., & Kokol, V. (­2015). Cytocompatibility and immunomodulatory properties of wood based nanofibrillated cellulose. Cellulose, 22(­1), 763–​­778. Cullen, M.B., Silcock, D.W., Boyle, C. (­2010). Wound dressing comprising oxidized cellulose and human recombinat collagen. U.S. Patent 7833790 B2. Curvello, R., Raghuwanshi, S.,  & Garnier, G. (­2019). Engineering nanocellulose hydrogels for biomedical applications. Advances in Colloid and Interface Science, 267, 47–​­61. Dai, H., Ou, S., Liu, Z.,  & Huang, H. (­2017). Pineapple peel carboxymethyl cellulose/­polyvinyl alcohol/­ mesoporous silica SBA-​­15 hydrogel composites for papain immobilization. Carbohydrate Polymers, 169, 504–​­514. Daneshmoghanlou, E., Miralinaghi, M., Moniri, E., & Sadjady, S.K. (­2022). Fabrication of a pH-​­responsive magnetic nanocarrier based on carboxymethyl cellulose-​­aminated graphene oxide for loading and in-​ v­ itro release of curcumin. Journal of Polymers and the Environment, 30, 3718–​­3736. Debele, T.A., Mekuria, S.L., & Tsai, H.C. (­2016). Polysaccharide based nanogels in the drug delivery system: Application as the carrier of pharmaceutical agents. Materials Science and Engineering: C, 68, 964–​­981. Debnath, B., Haldar, D., & Purkait, M. K. (­2021). A critical review on the techniques used for the synthesis and applications of crystalline cellulose derived from agricultural wastes and forest residues. Carbohydrate Polymers, 273, 118537. Del Valle, L. J., Díaz, A., & Puiggalí, J. (­2017). Hydrogels for biomedical applications: Cellulose, chitosan, and protein/­peptide derivatives. Gels, 3(­3), 27. Du, H., Liu, W., Zhang, M., Si, C., Zhang, X., & Li, B. (­2019). Cellulose nanocrystals and cellulose nanofibrils based hydrogels for biomedical applications. Carbohydrate Polymers, 209, 130–​­144. Fan, X., Yang, L., Wang, T., Sun, T., & Lu, S. (­2019). pH-​­responsive cellulose-​­based dual drug-​­loaded hydrogel for wound dressing. European Polymer Journal, 121, 109290 Ghaderi, M., Mousavi, M., Yousefi, H., & Labbafi, M. (­2014). All-​­cellulose nanocomposite film made from bagasse cellulose nanofibers for food packaging application. Carbohydrate Polymers, 104, 59–​­65. 2020). Doxorubicin-​­ loaded carboxymethyl cellulose/­ Starch/­ ZnO nanoGholamali, I.,  & Yadollahi, M. (­ composite hydrogel beads as an anticancer drug carrier agent. International Journal of Biological Macromolecules, 160, 724–​­735. Ghorpade, V. S., Yadav, A. V.,  & Dias, R. J. (­ 2016). Citric acid crosslinked cyclodextrin/­ hydroxypropylmethylcellulose hydrogel films for hydrophobic drug delivery. International Journal of Biological Macromolecules, 93, 75–​­86. González-​­Torres, M., Leyva-​­Gómez, G., Rivera, M., Krötzsch, E., Rodríguez-​­Talavera, R., Rivera, A. L., & Cabrera-​­Wrooman, A. (­2018). Biological activity of radiation-​­induced collagen–​­polyvinylpyrrolidone–​ ­ EG hydrogels. MAterials Letters, 214, 224–​­227. P Guan, Y., Bian, J., Peng, F., Zhang, X. M., & Sun, R.C. (­2014). High strength of hemicelluloses based hydrogels by freeze/­thaw technique. Carbohydrate Polymers, 101, 272–​­280. Gupta, A., Keddie, D.J., Kannappan, V., Gibson, H., Khalil, I.R., Kowalczuk, M., Martin, C., Shuai, X.,  & Radecka, I. (­2019). Production and characterisation of bacterial cellulose hydrogels loaded with curcumin encapsulated in cyclodextrins as wound dressings. European Polymer Journal, 118, 437–​­450. Hasanah, A. N., Muhtadi, A., Elyani, I., & Musfiroh, I. (­2015). Epichlorohydrin as crosslinking agent for synthesis of carboxymethyl cellulose sodium (­Na-​­CMC) as pharmaceutical excipient from water hyacinth (­Eichorrnia crassipes L.). International Journal of Chemical Science, 13(­3), 1227–​­37. Heidarian, P., Gharaie, S., Yousefi, H., Paulino, M., Kaynak, A., Varley, R., & Kouzani, A. Z. (­2022). A 3D printable dynamic nanocellulose/­nanochitin self-​­healing hydrogel and soft strain sensor. Carbohydrate Polymers, 291, 119545.

250

Cellulose

Hickey, R. J., & Pelling, A. E. (­2019). Cellulose biomaterials for tissue engineering. Frontiers in Bioengineering and Biotechnology, 7, 45. Ho, T.C., Chang, C.C., Chan, H.P., Chung, T.W., Shu, C.W., Chuang, K.P., Duh, T.H., Yang, M.H., & Tyan, Y.C. (­2022). Hydrogels: Properties and applications in biomedicine. Molecules, 27, 2902. Horta-​­Velázquez, A.,  & Morales-​­Narváez, E. (­2022). Nanocellulose in wearable sensors. Green Analytical Chemistry, 1, 100009. Aghdam, S.J., Foroughi-​­ Nia, B., Zare-​­ Akbari, Z., Mojarad-​­ Jabali, S., Motasadizadeh, H.,  & Hossieni-​­ Farhadnejad, H. (­2018). Facile fabrication and characterization of a novel oral pH-​­sensitive drug delivery system based on CMC hydrogel and HNT-​­AT nanohybrid. International Journal of Biological Macromolecules, 107, 2436–​­2449. Huber, T., Feast, S., Dimartino, S., Cen, W., & Fee, C. (­2019). Analysis of the effect of processing conditions on physical properties of thermally set cellulose hydrogels. Materials, 12(­7), 1066. Hussey, G.S., Dziki, J.L., & Badylak, S.F. (­2018). Extracellular matrix-​­based materials for regenerative medicine. Nature Review Materials, 3, 159–​­173. Jacob, S., Nair, A., Shah, J., Sreeharsha, N., Gupta, S., & Shinu, P. (­2021). Emerging role of hydrogels in drug delivery systems, tissue engineering and wound management. Pharmaceutics, 13, 357. Jagur-​­Grodzinski, J. (­2011). Polymeric gels and hydrogels for biomedical and pharmaceutical applications. Polymers for Advanced Technologies, 21, 27–​­47. Javanbakht, S.,  & Namazi, H. (­2018). Doxorubicin loaded carboxymethyl cellulose/­graphene quantum dot nanocomposite hydrogel films as a potential anticancer drug delivery system. Materials Science and Engineering: C, 87, 50–​­59. Javanbakht, S., & Shaabani, A. (­2019). Carboxymethyl cellulose-​­based oral delivery systems. International Journal of Biological Macromolecules, 133, 21–​­29. Jiang, L., Han, Y., Xu, J., & Wang, T. (­2022). Preparation and study of c­ ellulose-​­based ZnO NPs@HEC/­­C-​­β-​ ­CD/­Menthol hydrogel as wound dressing. Biochemical Engineering Journal, 184, 108488. 2020). Cellulose nanocomposites: Joseph, B., Sagarika, V.K., Sabu, C., Kalarikkal, N.,  & Thomas, S. (­ Fabrication and biomedical applications. Journal of Bioresources and Bioproducts, 5(­4), 223–​­237. Kaco, H.A.T.I.K.A., Zakaria, S., Razali, N.F., Chia, C.H., Zhang, L., & Jani, S.M. (­2014). Properties of cellulose hydrogel from kenaf core prepared via pre-​­cooled dissolving method. Sains Malaysiana, 43(­8), 1221–​­1229. Kanafi, N. M., Rahman, N. A., & Rosdi, N. H. (­2019). Citric acid cross-​­linking of highly porous carboxymethyl cellulose/­poly (­ethylene oxide) composite hydrogel films for controlled release applications. Materials Today: Proceedings, 7, 721–​­731. Khoylou, F.,  & Naimian, F. (­2009). Radiation synthesis of superabsorbent polyethylene oxide/­tragacanth hydrogel. Radiation Physics and Chemistry, 78(­3), 195–​­198. Koivuniemi, R., Hakkarainen, T., Kiiskinen, J., Kosonen, M., Vuola, J., Valtonen, J., Luukko, K., Kavola, H., & Yliperttula, M. (­2020). Clinical study of nanofibrillar cellulose hydrogel dressing for skin graft donor site treatment. Advanced in Wound Care, 9, 199–​­210. Lamaming, J., Hashim, R., Sulaiman O., & Leh, C.P. (­2017). Properties of cellulose nanocrystal from oil palm trunk isolated by total chlorine free method. Carbohydrate Polymers, 156, 409–​­416. Lamaming, J., Hashim, R., Sulaiman O., Leh, C P., Sugimoto, T., & Nordin, N.A. (­2015). Cellulose nanocrystal isolated from oil palm trunk. Carbohydrate Polymers, 127, 202–​­208. Lu, M., Liu, Y., Huang, Y.C., Huang, C.J., & Tsai, W.B. (­2018). Fabrication of photo-​­crosslinkable glycol chitosan hydrogel as a tissue adhesive. Carbohydrate Polymers, 181, 668–​­674. Lu, Y., Biswas, M.C., Guo, Z., Jeon, J.W., & Wujcik, E.K. (­2019). Recent developments in bio-​­monitoring via advanced polymer nanocomposite-​­based wearable strain sensors. Biosensors and Bioelectronics, 123, 167–​­177. Luo, H., Cha, R., Li, J., Hao, W., Zhang, Y., & Zhou F. (­2019). Advances in tissue engineering of nanocellulose-​ b­ ased scaffolds: A review. Carbohydrate Polymers, 224, 115144. Mali, K. K., Dhawale, S. C., Dias, R. J., Dhane, N. S., & Ghorpade, V. S. (­2018). Citric acid crosslinked carboxymethyl cellulose-​­based composite hydrogel films for drug delivery. Indian Journal of Pharmaceutical Sciences, 80(­4), 657–​­667. Manikandan, N. A.,  & Lens, P. N. (­2022). Green extraction and esterification of marine polysaccharide (­ulvan) from green macroalgae Ulva sp. using citric acid for hydrogel preparation. Journal of Cleaner Production, 366, 132952. Mandal, B., & Ray, S. K. (­2016). Removal of safranine T and brilliant cresyl blue dyes from water by carboxy methyl cellulose incorporated acrylic hydrogels: Isotherms, kinetics and thermodynamic study. Journal of the Taiwan Institute of Chemical Engineers, 60, 313–​­327.

Developments and Applications of NC-Based Hydrogels

251

Maturavongsadit, P., Narayanan, L. K., Chansoria, P., Shirwaiker, P., & Benhabbou, S.R. (­2021). Cell-​­laden nanocellulose/­chitosan-​­based bioinks for 3D bioprinting and enhanced osteogenic cell differentiation. ACS Applied Bio Materials, 4(­3), 2342–​­2353. Md Abu, T., Zahan, K.A., Rajaie, M.A., Leong, C.R., Ab Rashid, S., Mohd Nor Hamin, N.S., Tan, W.N., & Tong, W.Y. (­2020). Nanocellulose as drug delivery system for honey as antimicrobial wound dressing. Materials Today Proceedings, 31, 14–​­17. Mischnick, P.,  & Momcilovic, D. (­2010). Chemical structure analysis of starch and cellulose derivatives. Advances in Carbohydrate Chemistry and Biochemistry, 64, 117–​­210. Misenan, M.S.M., Akhlisah, Z.N., Shaffie, A.H., Saad, M.A.M., & Norrrahim, M.N.F. (­2022). 8-​­Nanocellulose in sensors. In Sapuan, S. M., Norrrahim, M. N. F., Ilyas, R. A., & Soutis, C. (­Eds.), Industrial Applications of Nanocellulose and Its Nanocomposites (­­pp. 213–​­243). Woodhead Publishing, Sawston. Nicu, R., Ciolacu, F.,  & Ciolacu, D.E. (­2021). Advanced functional materials based on nanocellulose for pharmaceutical/­medical applications. Pharmaceutics, 13(­8), 1125. Parhi, R. (­2017). Cross-​­linked hydrogel for pharmaceutical applications: A review. Advanced Pharmaceutical Bulletin, 7(­4), 515–​­530. Patel, D.K., Dutta, S.D., Shin, W.C., Ganguly, K., & Lim, K.T. (­2021). Fabrication and characterization of 3D printable nanocellulose-​­based hydrogels for tissue engineering. RSC Advances, 11, 7466–​­7478. Pereira, D.R., ­Silva-​­Correia, J., Oliveira, J.M., Reis, R.L., Pandit, A., & Biggs, M.J. (­2018). Nanocellulose reinforced ­gellan-​­gum hydrogels as potential biological substitutes for annulus fibrosus tissue regeneration. Nanomedicine: Nanotechnology, Biology and Medicine, 14(­3), ­897–​­908. Pooresmaeil, M., Javanbakht, S., Nia, S.B., & Hamazi, H. (­2020). Carboxymethyl cellulose/­mesoporous magnetic graphene oxide as a safe and sustained ibuprofen delivery bio-​­system: Synthesis, characterization, and study of drug release kinetic. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 594, 124662 Portela, R., Leal, C.R., Almeida, P.L., & Sobral, R.G. (­2019). Bacterial cellulose: A versatile biopolymer for wound dressing applications. Microbial Biotechnology, 12(­4), 586–​­610. Pradeep, H.K., Patel, D.H., Onkarappa, H.S., Pratiksha, C.C., & Prasanna, G.D. (­2022). Role of nanocellulose in industrial and pharmaceutical ­sectors -​­A review. International Journal of Biological Macromolecules, 207, ­1038–​­1047. Qi, C., Liu, J., Jin, Y., Xu, L., Wang, G., Wang, Z., & Wang, L. (­2018). Photo-​­crosslinkable, injectable sericin hydrogel as 3D biomimetic extracellular matrix for minimally invasive repairing cartilage. Biomaterials, 163, 89–​­104. Rao, Z., Ge, H., Liu, L., Zhu, C., Min, L., Liu, M., Fan, L.,  & Li, D. (­2018). Carboxymethyl cellulose modified graphene oxide as pH-​­sensitive drug delivery system. International Journal of Biological Macromolecules, 107, 1184–​­1192. Ramadan, Q., & Zourob, M. (­2021). 3D bioprinting at the frontier of regenerative medicine, pharmaceutical, and food industries. Frontiers in Medical Technology, 2, 607648. Ribeiro, A.M., Magalhães, M., Veiga, F., & Figueiras, A. (­2018). Cellulose-​­Based Hydrogels in Topical Drug Delivery: A challenge in medical devices. In Mondal, M.I.H. (­Ed.), ­Cellulose-​­Based Superabsorbent Hydrogels (­1st ed., ­pp. 1–​­29). Springer Nature, Switzerland. Reddy, N., Reddy, R., & Jiang, Q. (­2015). Crosslinking biopolymers for biomedical applications. Trends in Biotechnology, 33(­6), 362–​­369. Rusu, D., Ciolacu, D., & Simionescu, B.C. (­2019). Cellulose-​­based hydrogels in tissue engineering applications. Cellulose Chemical and Technology, 53, 907–​­923. Saddique, A., & Cheong, I.W. (­2021). Recent advances in three-​­dimensional bioprinted nanocellulose-​­based hydrogel scaffolds for biomedical applications. Korean Journal of Chemical Engineering, 38, 2171–​­2194. Sagar, S., Mandaloju, S., Lavanya, S., Nanjwade, B., & Reddy, B. (­2018). Hydrogels as advanced bio-​­materials for drug delivery system. Asian Journal of Science and Technology, 9(­5), 8117–​­8125. Saiki, S., Nagasawa, N., Hiroki, A., Morishita, N., Tamada, M., Kudo, H., & Katsumura, Y. (­2011). ESR study on radiation-​­induced radicals in carboxymethyl cellulose aqueous solution. Radiation Physics and Chemistry, 80(­2), 149–​­152. Sezer, S., Şahin, İ., Öztürk, K., Şanko, V., Koçer, Z., & Sezer, Ü.A. (­2019). Cellulose-​­based hydrogels as biomaterials. In Mondal, M. H. (­ed) ­Cellulose-​­Based Superabsorbent Hydrogels (­­pp. 1177–​­1203). Springer, Cham. Sharma, A., Thakur, M., Bhattacharya, M., Mandal, T., & Goswami, S. (­2019). Commercial application of cellulose nano-​­composites–​­A review. Biotechnology Reports, 21, e00316. Shefa, A.A., Sultana, T., Park, M.K., Lee, Y.S., Gwon, J., & Lee, B. (­2020). Curcumin incorporation into an oxidized cellulose nanofiber-​­polyvinyl alcohol hydrogel system promotes wound healing. Materials and Design, 186, 108313

252

Cellulose

Shojaeiarani, J., Bajwa, D., & Shirzadifar, A. (­2019). A review on cellulose nanocrystals as promising biocompounds for the synthesis of nanocomposite hydrogels. Carbohydrate Polymers, 216, 247–​­259. Singh, B., & Bala, R. (­2014). Development of hydrogels by radiation induced polymerization for use in slow drug delivery. Radiation Physics and Chemistry, 103, 178–​­187. Sirajuddin, N.A., Jamil, M.S.M., & Lazim, M.A.S.M. (­2014). Effect of cross-​­link density and the healing efficiency of self-​­healing poly (­2-​­hydroxyethyl methacrylate) hydrogel. ­e-​­Polymers, 14(­4), 289–​­294. Song, S., Liu, Z., Abubaker, M.A., Ding, L., Zhang, J., Yang, S.,  & Fan Z. (­2021). Antibacterial polyvinyl alcohol/­bacterial cellulose/­nano-​­silver hydrogels that effectively promote wound healing. Materials Science & Engineering: C, 126, 112171. Subhedar, A., Bhadauria, S., Ahankari, S., & Kargarzadeh, H. (­2021). Nanocellulose in biomedical and biosenesing applications: A review. International Journal of Biological Macromolecules, 166, 587–​­600. Tanpichai, S. (­2022). Recent development of plant-​­derived nanocellulose in polymer nanocomposite foams and multifunctional applications: A mini-​­review. Express Polymer Letters, 16(­1), 52–​­74. Tosh, B. (­2015). Esterification and etherification of cellulose: Synthesis and application of cellulose derivatives. In Mondal, I. H. (­ed) Cellulose and Cellulose Derivatives: Synthesis, Modification and Applications, (­­pp. 259–​­298). Nova Science Publishers Inc, New York. Uyanga, K.A., Okpozo, O.P., Onyekwere, O.S.,  & Daoud, W.A. (­2020). Citric acid crosslinked natural bi-​ ­polymer-​­based composite hydrogels: Effect of polymer ratio and beta-​­cyclodextrin on hydrogel microstructure. Reactive and Functional Polymers, 154, 104682. Wach, R. A., Rokita, B., Bartoszek, N., Katsumura, Y., Ulanski, P., & Rosiak, J.M. (­2014). Hydroxyl radical-​ ­induced crosslinking and radiation-​­initiated hydrogel formation in dilute aqueous solutions of carboxymethyl cellulose. Carbohydrate Polymers, 112, 412–​­415. Wang, F., Huang, K., Xu, Z., Shi, F., & Chen, C. (­2022). Self-​­healable nanocellulose composite hydrogels combining multiple dynamic bonds for drug delivery. International Journal of Biological Macromolecules, 203,143–​­152. Yang, G., Zhang, Z., Liu, K., Ji, X., Fatehi, P., & Chen, J. (­2022). A cellulose nanofibril-​­reinforced hydrogel with robust mechanical, self-​­healing, pH-​­responsive and antibacterial characteristics for wound dressing applications. Journal of Nanobiotechnology, 20, 312. Yin, O.S., Ahmad, I., & Amin, M.C.I.M. (­2015). Effect of cellulose nanocrystals content and pH on swelling behaviour of gelatin based hydrogel. Sains Malaysiana, 44(­6), 793–​­799. Yom-​­Tov, O., Seliktar, D., & Bianco-​­Peled, H. (­2016). PEG-​­Thiol based hydrogels with controllable properties. European Polymer Journal, 74, 1–​­12. Yu, S., Zhang, X., Tan, G., Tian, L., Liu, D., Liu, Y., Yang, X., & Pan, W. (­2017). A novel pH-​­induced thermosensitive hydrogel composed of carboxymethyl chitosan and poloxamer cross-​­linked by glutaraldehyde for ophthalmic drug delivery. Carbohydrate Polymers, 155, 208–​­217. Yuan, M., Bi, B., Huang, J., Zhuo, R., & Jiang, X. (­2018). Thermosensitive and photocrosslinkable hydroxypropyl chitin-​­based hydrogels for biomedical applications. Carbohydrate Polymers, 192, 10–​­18. Zhang, Q., Zhu, S., Zheng, Y., Gao, W., Wu, D., Yu, J., & Dai, Z. (­2022). Cellulose-​­nanofibril-​­reinforced hydrogels with pH sensitivity and mechanical stability for wound healing. Materials Letters, 323, 132596. Zhang, X., Wu, D., & Chu, C.C. (­2004). Synthesis and characterization of partially biodegradable, temperature and pH sensitive Dex–​­MA/­PNIPAAm hydrogels. Biomaterials, 25(­19), 4719–​­4730. Zhao, J., He, X., Wang, Y., Zhang, W., Zhang, X., Zhang, X., & Lu, C. (­2014). Reinforcement of all-​­cellulose nanocomposite films using native cellulose nanofibrils. Carbohydrate Polymers, 104, 143–​­150. Zhao, Y., He, M., Jin, H., Zhao, L., Du, Q., Deng, H., Tian, W., Li, Y., Lv, X., & Chen, Y. (­2018). Construction of highly biocompatible hydroxyethyl cellulose/­soy protein isolate composite sponges for tissue engineering. Chemical Engineering Journal, 341, 402–​­413. Zhao, Y., Shen, W., Chen, Z.,  & Wu, T. (­2016). Freeze-​­thaw induced gelation of alginates. Carbohydrate Polymers, 148, 45–​­51. Zheng, C., Yue, Y., Gan, L., Xu, X., Mei, C., & Han, J. (­2019). Highly stretchable and self-​­healing strain sensors based on nanocellulose-​­supported graphene dispersed in electro-​­conductive hydrogels. Nanomaterials, 9(­7), 937.

17

Overview of Cellulose Fiber as Materials for Paper Production Nurul Syuhada Sulaiman Universiti Sains Malaysia

CONTENTS Introduction..................................................................................................................................... 253 Cellulose Fiber Sources.................................................................................................................. 254 Wood.......................................................................................................................................... 254 ­Non-​­Wood.................................................................................................................................. 255 Recycled Fiber........................................................................................................................... 255 Rags............................................................................................................................................ 256 Pulp and Paper Manufacturing Process in Paper Industry.............................................................. 256 Pulping Methodology..................................................................................................................... 257 Mechanical Pulping.................................................................................................................... 258 ­Chemi-​­Mechanical Pulping........................................................................................................ 259 ­Semi-​­Chemical Pulping............................................................................................................. 259 Chemical Pulping....................................................................................................................... 259 Bio Pulping................................................................................................................................260 Bleaching...................................................................................................................................260 Pulp Blending............................................................................................................................. 261 Pulp Beating/­Refining........................................................................................................... 261 Additives................................................................................................................................ 261 Papermaking............................................................................................................................... 263 Forming and Dewatering.......................................................................................................264 Pressing.................................................................................................................................264 Drying.................................................................................................................................... 265 Calendering...........................................................................................................................266 Reeling and Winding.............................................................................................................266 Conclusion......................................................................................................................................266 References....................................................................................................................................... 267

INTRODUCTION Paper is a thin sheet of fiber network (­frequently manufactured from cellulose fiber) bound to each other on a fine screen upon dewatering. The modern word “­paper” was initiated from the papyrus plant, a ­grass-​­like aquatic plant with a woody and bluntly triangle stem. The papyrus paper was first invented in Egypt as this plant was abundantly available along the riverside of the Nile River. The formation of papyrus paper was started by removing the outer rind of its long stem. Then, the stem was lengthwise cut into thin strips of about 40 cm long, exposing its sticky fibrous inner pith. The strips were then placed side by side with their edges slightly overlapping, and the other layer was put on the top at right angles. The layers were dampened, hammered into a single sheet, and dried under pressure. The sticky fibrous inner pith will cement the layers together, acting as an adhesive upon drying. Papyrus is highly stable in a dry climate like Egypt due to its highly ­rot-​­resistant cellulose DOI: 10.1201/9781003358084-17

253

254

Cellulose

fiber. Cellulose fiber is paper’s primary and essential structural element, which contributes about 90%–​­99% of its content, significantly impacting end product properties.

CELLULOSE FIBER SOURCES Cellulose fiber is a long, linear polysaccharide that serves as the plant cell wall’s primary l­oad-​ ­bearing component. Technically, the term cellulose fiber is referring to as fiber that is composed of cellulose as a major constituent, followed by hemicellulose and lignin. Meanwhile, cellulose is a linear polysaccharide composed of glucose derivatives that makes up the cellulose fiber. The cellulose fiber is very high in strength and durability and has excellent flexibility. The colors can be white to colorless after the removal of impurities. Cellulose fiber is ­water-​­insoluble, despite being hydrophilic. It is chemically stable and can form physical and chemical bonding with other fibers when the condition changes from wet to dry. These combinations of cellulose fiber properties make cellulose a very suitable raw material for papermaking. Additionally, various sources of fiber have different morphological and chemical characteristics. Therefore, cellulose fibers can be suitable for producing different grades of final products.

Wood Wood is the predominant and preferable source of cellulose fiber in paper production. Cellulose fiber from trees or wood falls into two categories: hardwood (­deciduous tree) and softwood (­coniferous tree). Poplars, maple, birch, sweetgum, and hickory are examples of hardwood trees that are suitable for producing sturdier printing paper and magazines. Meanwhile, softwood trees such as hemlocks, pines, firs, and spruces serve as excellent cellulose fiber sources for papermaking. The properties of paper and ­paper-​­based products are highly influenced by cellulose fiber’s physical properties, such as breadth (­broad), cell wall thickness, and length. Due to this, vigilant choices of cellulose fiber sources need to be made. Cellulose fiber properties vary depending on the types of wood, species, the percentage of juvenile wood and mature wood, the ratio of earlywood (­springwood) to latewood (­summerwood), and the type of pulping process (­Cameron, 2004). The length of softwood cellulose fibers ranges from about 2 to 6 mm and ­20–​­60 μm in width, while the length of hardwood fibers measures from about 0.7 to 1.7 mm and ­14–​­40 μm in width. The other difference in morphology between softwood and hardwood is that softwood generates fiber with less cell wall thickness than hardwood. The thick cell wall fiber has poor collapsibility, leading to poor bonding between the fibers and a low rigidity coefficient. The rigidity coefficient is calculated by dividing cell wall thickness with diameter and multiplying by a hundred. Rigid fibers, as in hardwood, are less elastic, negatively affecting paper resistance properties. Thus, it is not suitable for paper production (­A kgül & Tozluoğlu, 2009). Another factor that needs to be considered is the tree’s ratio of latewood and earlywood. Latewood is composed of fiber with a thick cell wall compared to earlywood. Thus, wood species with a high proportion of latewood than softwood tend to produce paper with low resistance properties. Juvenile wood is short fiber xylem at the core with high microfibril angles (­Shmulsky & Jones, 2019). In comparing the percentage of juvenile and mature wood, wood species containing a greater proportion of juvenile wood will produce paper with excellent properties due to its lower cell wall thickness. Softwood has gained much more interest for papermaking than hardwood due to ease and less energy required to convert them into paper, in consort with its good fiber properties that give rise to good quality of the end product. A long fiber associated with softwood is advantageous in providing high felting power during paper production. High felting power positively affects the physical properties of paper, such as tear resistance, double folding resistance, burst, breaking off, and strength. However, hardwood fibers have an advantage in providing paper with high opacity and smooth surface properties, which is good for sturdier paper products. Therefore, some paper products must

Overview of Cellulose Fiber as Materials for Paper Production

255

be made from a mixture of softwood and hardwood fibers to gain specifically targeted properties of the end products. The depletion of forest resources due to the rapid and vast increasing consumption of wood for pulp has gained attention. Therefore, a new interest in utilizing other cellulose fiber sources has been developed. Cellulose fiber sources from ­non-​­wood such as kenaf, bamboo, hemp, and cotton and waste from wood mills such as sawdust, recycled paper, and paperboard have been investigated. Some of them are readily commercialized.

­Non-​­Wood Cellulose fiber from ­non-​­wood sources is one of the good alternatives to reduce wood consumption in the papermaking industry, especially in a less developed country where few forest resources are available, and paper consumption is comparatively low. Paper production using ­non-​­wood is frequently produced on a small scale, and low capital investment with its sources comes from local annual fiber that is suited for local markets. The essential characteristic of ­non-​­wood is its vascular bundle. Tracheid, fiber, and vessels are embedded in this vascular bundle, surrounded by parenchyma tissue. There are four categories of n­ on-​­wood: (­1) annual fiber crops (­hemp, kenaf, sisal, jute), (­2) agricultural residue (­wheat, corn, wheat straw, rice straw, bagasse, empty fruit bunch, oil palm frond, oil palm trunk), (­3) wild plants (­grasses, bamboo, seaweed), and (­4) ­well-​­defined wastes (­cow dung, kangaroo poo). Straw is a standard ­non-​­wood used in the pulp and papermaking industry, followed by bagasse and bamboo. Straw has a short fiber similar to hardwood fiber and contains high silica content, which is typical for ­non-​­wood resources. Compared to wood, ­non-​­wood plant fiber is thinner and has less cellulose and lignin but is high in hemicellulose, silica, and ash. These characteristics result in a low pulp yield that is high in purity. By contrast, high pulp yield produced from ­non-​­woody sources contain a high number of extractives. Therefore, paper made from only n­ on-​­wood cellulose fiber tends to be stiff and dense, with low opacity and tear resistance. However, pulp and paper produced from ­non-​­wood like kenaf, hemp, and flax will exhibit high quality and are frequently used for unique papers such as banknotes and cigarette papers. The ­non-​­wood plant contains many nonfibrous cells (­parenchyma cells), which differ entirely from coniferous wood (­softwood). Nonfibrous cells are less desirable in paper manufacturing than fibers. Still, the mixture of these two results in paper with high opacity due to the filling of the void by nonfibrous cells during the papermaking process. This morphology is similar to deciduous wood (­hardwood) as hardwood frequently comprises many nonfibrous cells. A milder pulping process is essential when using ­non-​­wood as a pulp precursor. Moreover, alkaline chemicals such as soda ash, lime, caustic soda, and kraft liquor are favorable to be used in the pulping process. Many researchers are still finding and working on n­ on-​­wood as a source for pulp and papermaking. They have utilized ­non-​­wood sources such as sugarcane bagasse (­Varghese et al., 2020), jute (­Day et al., 2006), kenaf (­Shakhes et al., 2011), bamboo (­Dwiky et al., 2019), rice straw (­Kaur et al., 2018), wheat straw (­Malik et al., 2020), rapeseed straw (­Mousavi et al., 2013), hemp (­Barberà et al., 2011; Danielewicz & ­Surma-​­Ślusarska, 2010; Lee et al., 2011; Miao et al., 2014), and flax (­Sain & Fortier, 2002). Researchers are focusing on finding new and best ways in the pulping process or are studying many aspects and factors that will affect paper properties.

Recycled Fiber Paper recycling is a process where waste paper is reprocessed to get the recycled fiber or secondary fiber for reuse. Utilizing recycled fiber helps reduce the need for virgin cellulose fiber in addition to reducing the problem of solid waste disposal. Wastepaper is obtained from scattered sources like paper mill, discarded paper materials such as corrugated waste from retail shops and manufacturing

256

Cellulose

plants, and materials discarded after consumer use such as old newspapers and magazines. Some wastepaper like packaging, wrapping papers, and corrugated boxes are typically checked for suitability before the recycling process. Paper recovery systems are categorized into two types: the recovery with the ­de-​­inking process and the recovery without a ­de-​­inking process. The ­de-​­inking recovery process was carried out by feeding wastepaper into a cylindrical tank pulper equipped with agitator blades, which agitates the wastepaper stock. This process separates and disperses the fibers using hot water at a temperature range from 65°C to 90°C and chemicals to disperse and dissolve the ink. Caustic soda, accompanied by silicate of soda, surfactants, or wetting agents, soda ash, and phosphates, is the most commonly used chemical. After that, the stock undergoes a screening process to remove fine foreign particles and dirt before washing the chemicals and dispersed ink. In some cases, the stock was subjected to a bleaching process employing hypochlorite to improve its whiteness. Meanwhile, the recovery process without needing ­de-​­inking was carried out the same way described above. The only difference is that hot water is used alone without adding chemicals during the pulping process. The printing grade or other white papers are frequently produced using the stock prepared with the ­de-​­inking process. Meanwhile, paper products such as coarse paper and boxboards are commonly prepared from the stock without d­ e-​­inking.

Rags Used cloth, also known as rags, is one of the sources of cellulose fiber, which has successfully been used as a primary precursor in producing paper. The paper that originated from this cotton linter or cotton from rags is called cotton paper, rag paper, or rag stock paper. Cotton paper is extensively used for important documents such as banknotes, security certificates, and archival copies of theses. Its high durability can last hundreds of years without deterioration, fading, or discoloration. Cotton paper can be produced with different grades and is typically graded as 25%, 50%, or 100% cotton. At the paper mill, rags are first sorted by hand to remove any foreign materials such as metal and rubber, disregarding rags comprising synthetic fibers and coatings that are tough to remove. Subsequently, those clean and selected rags are cut and dusted to remove small particles of foreign materials before the removal of iron by passing those rags over magnetic rolls. After that, the rags were cooked in a large cylindrical boiler for ­3 –​­10 h under pressure to remove any oils, natural waxes, grease, and fillers. Each part of the rags was cooked with approximately three parts of cooking liquor, soda ash or caustic soda with detergents or wetting agents, and a dilute alkaline solution of lime. Next, the rags are washed before being mechanically beaten. The beating action will optimally modify the fibers by (­1) shortening the fiber on an excellent paper formation, (­2) making them swell for more conformable and stronger paper, and (­3) fibrillates the fiber to increase its surface area and improving bonding ability of the fibers, for a strong, smooth, and good printing paper.

PULP AND PAPER MANUFACTURING PROCESS IN PAPER INDUSTRY The pulp and paper industry are huge, operating with a wide variety of pulping and papermaking processes that utilize a wide variety of fiber sources. The primary substance in pulp and paper manufacturing is cellulose fiber. Meanwhile, the main process is divided into two: stock preparation and papermaking. The primary objectives of stock preparation are to take the required fibrous raw materials (­pulps) and nonfibrous components (­additives) and modify each furnish constituent as needed. The second objective is to combine all the ingredients continuously and uniformly into the papermaking stock. Stock is a mixture (­slurry) of pulp, fillers, other papermaking materials, and

257

Overview of Cellulose Fiber as Materials for Paper Production RAW MATERIAL PREPARATION DEBARKING CUTTING PULP MAKING DIGESTION SCREENING

STOCK PREPARATION BLEACHING

BEATING REFINING ADDITIVES: ·SIZING ·FILLERS ·ADHESIVES ·DYES

PULP BLENDING

FORMING

PRESSING

DRYING

PAPERMAKING

CALENDERING

REELING

­FIGURE 17.1 

Basic processes in pulp and papermaking.

water. Meanwhile, furnish is the combination of all of the materials used to make paper. The basic processes in typical paper manufacturing are depicted in ­Figure 17.1. There are numerous types and grades of paper that can be produced, and the differences between them are determined by several factors:

1. Types of fiber 2. Beating or refining degree of the stock 3. Addition of additives to the stock 4 Formation condition of the sheet, including grammage (­basic weight) 5. Application of physical or chemical treatment to the sheet

PULPING METHODOLOGY Generally, the pulping process is a p­ ulp-​­making process that is carried out by separating and treating cellulose fibers. Pulping processes are categorized into five types: mechanical pulping, chemical pulping, ­chemi-​­mechanical pulping (­CMP), s­ emi-​­chemical pulping, and biopulping. The overview of all of these pulping processes is presented in ­Table 17.1.

258

Cellulose

­TABLE 17.1 Comparison Between Five Types of Pulping Methodology ­Chemi-​ ­Mechanical Pulping

­Semi-​­Chemical Pulping

No chemical, ­grind-​­stones for logs; disc refiner for chip ­92–​­96 Short, impure fibers High opacity, softness, bulk, low strength, and brightness

Modest chemical impregnation, ­CTMP-​­NaOH, NaHSO3 ­85–​­95 Intermediate

Partially softened or cooked with chemicals and mild disc refining, NSSP ­55–​­85 Intermediate

High opacity, bulk, and moderate strength

Good stiffness and moldability

Newsprint, books, magazines

Newsprint, books, magazines

Corrugating medium

Mechanical Pulping Chemicals

Yield (%) Pulp properties Paper properties

End uses

Chemical Pulping

Biopulping

Only chemicals and heat. Kraft, soda, sulfite

No chemicals, fungi, enzymes

­40–​­55 Long, strong fibers High strength, light brown to dark brown pulps (­depend on pulping chemicals) Wrapping, linerboard, white paper, tissue

­43–​­63 Intermediate High strength and high brightness

White paper

Mechanical Pulping Mechanical pulping uses mechanical action to defibrillate the cellulose fibers into fiber bundles without removing other contents such as lignin, hemicellulose, and extractives. Mechanical pulping can further be categorized into two subgroups: stone groundwood (­SGW) and refiner mechanical pulping (­R MP). SGW pulping uses a wet log as its cellulose fiber source. SGW is carried out by exposing wood to a grinding action and applying pressure to ensure contact and friction between the wood and the spinning grinding stone. The rough surface of the grinder is made of aluminum oxide or silicon carbide (­SiC), usually lasting for 2 years. Mechanical pulping is performed by cutting the log to a shorter length before being debarked and fed into the grinder. The log moisture content is a crucial factor that must be dealt with to ease the grinding process and ensure the pulp’s quality. The minimum moisture content of the log should be at least 30% and most preferably at 45%–​­50%. The pulp formed enters the pit that acts as a pulp pool before getting through to a series of rifflers and screens that separate the heavy foreign material such as shives, knots, and bark. The resulting pulp is in the form of a cluster of fibers with considerable amounts of debris. In addition, other chemical constituents of wood like lignin, hemicellulose, and extractives are still present in the resulting pulp. Thus, paper produced using mechanical wood pulp tends to become yellowish over time and after exposure to heat and light such as newspaper. Due to the shorter fiber length and moderate ability of the fiber to bond to each other, paper manufactured from mechanical pulp resulted in low strength properties. However, the positive effect of paper containing mechanical pulp is that it has good opacity, is bulky, and has good printing qualities. Another mechanical pulping type is RMP. Instead of the log, RMP uses a precursor in the form of a chip. The refiners have two discs with controllable gaps, and the discs are further classified into two types according to their spinning nature. The first type of disc was spinning in the opposite direction. Meanwhile, the other type has one stationary disc and one spinning disc. Two refining stages occur in RMP, with the first stage having a more significant breaking zone but a smaller refining zone and the other way around for the second stage. The first refining stage has a disc with

Overview of Cellulose Fiber as Materials for Paper Production

259

three zones bar with valleys of varying sizes. The first zone is the coarse zone (­breaking zone) with a large bar, deep valley, and function to break the wood chip into particles. The second zone is the middle zone with a smaller bar and shallow valley and plays a role in refining the particle further. Meanwhile, the last zone is the fine zone with a smaller bar and shallow valley that plays a role as a particle converter to the pulp. The pulp formed is then screened and washed before the papermaking process. The pulp formed using RMP is much longer, more robust, and darker than SGW.

­Chemi-​­Mechanical Pulping CMP is the pulping method that combines chemical and mechanical actions. The chemical action softens the lignin, while the mechanical action liberates the fibers. Neutral sulfite s­ emi-​­chemical and ­chemi-­​­­thermo-​­mechanical pulping (­CTMP) are pulping methodologies that are categorized under CMP pulping. Neutral sulfite s­ emi-​­chemical is famous for pulping mixed hardwood species. The chemical used during the pulping process is sodium sulfite (­Na2SO3) and sodium carbonate (­Na2CO3). Once done, refining action takes place to separate the cellulose fiber further. Meanwhile, ­chemi-­​­­thermo-​­mechanical pulping utilized heat to ­pre-​­stim the fiber sources, followed by chemical impregnation and refining.

­Semi-​­Chemical Pulping ­ emi-​­chemical pulping is started by steeping and impregnating the cellulose fiber sources in the S chip form, with inorganic chemical solutions like sodium sulfite, in a smaller amount and under less severe conditions. Once the impregnation is done, the chips are transferred into the disc refiners. The refining process is responsible for converting the softened chips to the pulp. The pulp produced has physical and chemical strength properties that are intermediate between the pulp produced from mechanical and chemical pulping. The resulting s­ emi-​­chemical pulp has found its uses in a wide range of papers and boards, where stiffness and strength are the vital ­properties—​­for example, corrugating medium is used as the interior layer of corrugated boxboards in a ­heavy-​­duty container.

Chemical Pulping Chemical pulping is a pulping methodology in which the pulp is obtained through only chemical action. The chemical serves as the agent to break down the lignin that binds the cellulose fiber together. The first step in chemical pulping is feeding the cellulose fiber source into a large vessel called a digester to cook the source with chemicals under high pressure and temperature. Once cooked, the pulp produced is washed before screening, bleaching (­if needed), and papermaking. Three principal processes are involved in chemical pulping: soda, sulfite, and kraft processes. The soda process was developed in 1851 by Burgess and Watt. The soda process makes use of only sodium hydroxide as the chemical agent. However, it tend to produce sodium hydroxide by mixing sodium carbonate (­Na2CO3) with calcium oxide (­CaO). The sulfite process is the following pulping process in the evolution of chemical pulping. Sulfurous acid is the cooking liquor that was used in this process. Sulfurous acid was prepared by mixing sulfur dioxide with either alkali metals (­elements in group 1 in the periodic table, e.g., lithium, sodium, and potassium) or alkaline earth hydroxide (­elements in group 2 in the periodic table, e.g., calcium and magnesium). This combination gives a highly acidic and aggressive system that dissolves most of the lignin that binds the cellulose fiber together. However, this very aggressive approach destroys the fibers’ primary wall, leading to the destruction of other components called hemicelluloses. Later, the kraft process (­sulfate process) is developed by modifying a soda process but is less aggressive (­not very high in pH). In the kraft process, the hemicellulose content is retained. Hemicellulose is essential in reinforcing the ­fiber–​­fiber bonds in the sheet of paper. Therefore, paper

260

Cellulose

manufactured from kraft pulp is durable and has greater strength than paper manufactured from soda and sulfite pulp. The kraft process involves a mixture of sodium hydroxide (­sodium carbonate (­Na2CO3) + calcium oxide (­CaO)) and sodium sulfide. The other advantage of using the kraft process is that the cooking liquor is recyclable, which is the most economically viable.

Bio Pulping Biopulping was invented in Sweden and United States at the early 1970s as a pretreatment before the pulping process (­Viikari et al., 2009). This method was first developed to cope the drawbacks facing by mechanical pulping, which are weaker pulp strength and high electricity consumption (­Atalla et al., 2004). The wood chip was pretreated with lignin, degrading fungi prior to pulping by mechanical action. The softened wood chip reduces the time and energy required during the mechanical pulping. Minor mechanical action subjected to the cellulose fiber sources results in high pulp strength, thus increasing the paper strength. Different groups of fungi cause different forms of degradation. White rot fungi, brown rot fungi, and soft rot fungi are types of fungi that have been applied in the pulping process. However, white rot fungus is the predominant type used due to its ability to degrade all of the cell wall components including lignin. Later, more microorganisms have been screened, and ­lignin-​­degrading enzymes are implemented. Several enzymes that play a role in the pulping process are laccase, hemicellulase (­xylanase), pectinase, and cellulase. They can be used individually or in combination of two or more. However, the combination of enzymes is more preferable as they can supporting each other’s activities. For examples, the combination of hemicellulase and cellulase gives a great impact on d­ e-​­inking, especially during the conversion of recycled cellulose fiber to pulp. Furthermore, processing conditions such as pH, incubation period, moisture content, oxygen availability, and temperature, and the presence of metal ions must be taken into account to ensure that the efficiency of the enzymes are not decreasing. Biopulping can serve as a ­cost-​­effective and green environmental process as well. This can reduce a huge amount of toxic wastewater, particularly from cooking chemicals during the chemical pulping process. Moreover, a simple bleaching method accompanied with a superior result can be achieved by biopulping, which can benefit particularly in kraft pulping.

Bleaching Bleaching is a chemical process of making pulp lighter and whiter in color. However, the bleaching process is unnecessary depending on the end products’ target properties. The cause of color in the pulp is the carbon chain (-​­C=­C-​­C=­C-​­C=­C-​­) with a conjugated double bond system in lignin. Therefore, the objective of bleaching can be achieved using two strategies: altering or removing the lignin. The selection of the strategy depends on the type of pulp. Bleaching by altering the lignin structure is preferable applied to mechanical pulp. Mechanical pulp has lignin still in the fiber. Lignin can prevent degradation of the produced paper due to the polyphenol content that acts as radical scavengers (­Małachowska et al., 2020). Therefore, bleaching by altering the conjugated double bond system of the lignin is suitable as the lignin is still preserved, while the bleaching objective can still be achieved. Meanwhile, lignin removal is the best strategy for chemical pulp. In chemical pulp, a small amount of lignin might remain on the cellulose fiber. Therefore, the pure pulp can be obtained by completely removing the lignin. Both altering and removal strategies use chlorine gas (­Cl2). However, using chlorine elements (­as the initial bleaching agent) in pulp bleaching will produce nasty ­by-​­products, including dioxin, furan, and polychlorinated biphenyls. Therefore, the pulp and paper industry has replaced chlorine elements with chlorine compounds like hypochlorous or hyperchloric acid. Two types of ­chlorine-​ f­ree bleaching are elementally ­chlorine-​­free (­ECF) and totally ­chlorine-​­free (­TCF). Elementally ­chlorine-​­free bleaching involves replacing all chlorine elements in a bleaching sequence with chlorine dioxide. Other ­chlorine-​­containing compounds such as hypochlorite and chlorine dioxide

Overview of Cellulose Fiber as Materials for Paper Production

261

have remained. Meanwhile, TCF bleaching avoids using chemicals with chlorine elements or compounds. The common bleaching agents used are oxygen, ozone, hydrogen peroxide, and peracid. TCF bleaching guarantees no chlorinated compounds are produced from the bleaching process, and the effluent produced is ­non-​­toxic.

Pulp Blending The operations involve pulp blending, including beating or refining and adding ­wet-​­end additives. Pulp Beating/­Refining Pulp beating or refining is a mechanical treatment of pulp fibers using a beater or refiner. The objective of beating and refining is to modify the fibers optimally for the demands of the particular papermaking furnish. So, the fibers can be formed into papers or paperboards of the desired properties. The term beating refers to the early days of papermaking when the beating was performed manually beating the pulp with a stick. Meanwhile, refining is used to describe the mechanical action on fibers accomplished by using a machine called a refiner. Beating and refining of cellulose fiber allow water to penetrate its structure, cause the fiber swell, making it flexible, and thus improve the bonding ability of the fibers. These properties develop strong, smooth printing papers and shorten too long fibers for a good paper formation. Moreover, this mechanical treatment causes the bundle of fibers (­especially in mechanical pulp) to separate and resulted in reduce drainage rate, producing ­high-​­density paper with high tensile strength and low porosity. Mechanical pulps are usually not further refined during stock preparation, but light postrefining is sometimes carried out for drainage control. Chemical pulps are beaten for up to several hours, depending on the application, before the beater is discharged. The unbeaten or unrefined pulp contributes to several problems during the papermaking process, including complex drainage rate, bad paper formation, and poor ­wet-​­web strength, and the paper produced has low power due to high porosity and high bulk. Bad paper formation will also happen if the pulp (­especially virgin pulp from softwood) is used without beating or refining. The pulp with long fiber will be tangled between itself and forming flocs before the pulps reach the papermaking wire machine. Meanwhile, ­wet-​­web produced from unbeaten or unrefined pulp is broken easily due to the structure of the unfebrile pulp that is slippery, inflexible, and cylindrical, and contributes to the less specific surface area for hydrogen bonding between the pulp fibers. Additives Additives are considered the primary precursor in papermaking other than cellulose fibers. In ­wet-​ ­end additives processes, a wide variety of mineral and chemical agents are added to the pulp stock, either to impart specific properties to the paper product (­functional additives) or to facilitate the papermaking process (­control additives). ­Batch-​­wise operation is frequently applied during the ­wet-​ ­end additives process. After adding additives, blending and metering processes are applied to form homogenous papermaking stock. ­Table 17.2 presents various types of additives and its application. Paper is seldom made only from fiber, except for blotting paper, filter paper, and special tissue paper. A particular chemical is used to control and help the stock flow, decrease foaming, and increase the retention of the filler and fine. Nonfibrous materials can be added to the stock as solid and liquid. Solid additives are commercially packed in a certain weight to avoid mistakes during weighting, but the price is relatively high. The addition of solid additives is suitable for “­­batch-​­wise” stocks (­during disintegration and beating). However, more paper mills use liquid additives. Liquid additives appear as solutions or suspensions depending on the economy or convenience. Storage and dispersion of liquid additives are more straightforward than solid additives. However, extra help (­like water supply systems) is needed for additive dilution from the suspension form. Addition of additives must be performed correctly to avoid any unexpected reaction. Not all additives are blended into the stock preparation stage. For additives that are being added to the dried paper, they

262

Cellulose

­TABLE 17.2 Various Types of Additives and Its Application Additive Acids and bases Alum Sizing agents (­rosin) Dry strength adhesives (­starches, gums) ­Wet-​­strength resins Fillers (­clay, tale, tio2) Coloring materials (­dyes and pigments) Retention aids Fiber flocculants Defoamers Drainage aids Optical brighteners Pitch control chemicals Simicides Specialty chemicals

Application Control pH Control pH, fix additives onto cellulose fibers, enhance retention Control penetration of liquids Enhance burst and tensile, add stiffness and pick resistance Impart wet strength of the paper Enhance optical and surface properties Impact desired color Enhance retention of fines and fillers Enhance sheet formation Enhance drainage and sheet formation Enhance water removal on wire Enhance apparent brightness Prevent deposition or accumulation of pitch Control microorganisms and slime growths Corrosion inhibitors, ­flame-​­proofing, ­anti-​­tarnish chemicals, etc.

are called ­dry-​­end additives. It is estimated that 10% of paper mills’ total operation cost comes from adding additives. Additives that affect paper properties are called functional additives. Sizing agents are one the functional additives that enable paper to resist paper penetration by fluids. Sizing can be carried out during stock preparation (­as ­wet-​­end additives) or to the surface of the dried paper (­as coatings). The rate of liquid penetration (­wetting) on paper depends on the contact angle pictured. There are two types of sizing: internal sizing and surface sizing. Internal sizing such as rosin will develop resistance to penetrate aqueous liquid, such as ink, throughout the paper. Water penetration is retarded by the nonpolar part of the sizing molecule. The polar part of the sizing molecule anchors to the fiber surface. It is added to the stock before the stock goes into the head box. Meanwhile, in surface sizing, starch is applied using different mechanisms from internal sizing and added at the size press part. Starch is sprayed at the paper surface, filling up paper capillaries and making water penetration much more difficult. Native starch is rarely used as an additive. In surface sizing, modified starch such as acid hydrolyzed (­thinned) starches, oxidized starches, cationic starches, and starch ethers are used. Other than surface sizing, s­ tarch-​­based additives are often used as flocculants and retention aids. These are regularly carried out by using cationic starches produced by a nucleophilic substitution reaction with tertiary or quaternary amines. Additionally, ­starch-​ ­based additives also can serve as a pigment retention enhancer by using cationic waxy starches as an additive. ­Starch-​­based additives are commonly used due to its low cost and its ability in increasing fiber bonding, which increase paper strength in burst and tensile strength. Fillers such as clay (­aluminum silicate), talcum powder (­magnesium silicate), calcium sulfate, zinc oxide, hydrated silica, hydrated alumina, zinc sulfide, barium sulfate, asbestos, and titanium dioxide are white minerals that fill spaces between fibers. Consequently, fillers improve paper density, opacity, optical properties (­brightness), and surface smoothness, as well as receptivity. These properties are suitable for writing or printing paper. It can also cut costs because the cost of a filler like clay (­also known as kaolin or china clay) is cheaper than fibers. Paperweight consists of 5%–​ 1­ 5% of filler. Too much filler reduces the paper’s strength. Alum is added together with the filler to hold the filler in the formed sheet as most fillers have no affinity to fibers. Calcium carbonate (­CaCO3) is a type of filler that cannot be used together with alum due to its acid reactivity. It is primarily used to improve brightness, opacity, and ink receptivity. Calcium carbonate also contributes

Overview of Cellulose Fiber as Materials for Paper Production

263

to good burning properties, and this makes paper with calcium carbonate as fillers find its specialty in cigarette paper. The absorption of dye by cellulose fiber gives color to paper. The absorption of the dye depends on the chemical nature of the dye, capillary pore of the fiber, and polarity of the fiber surface. Three principal types of w ­ ater-​­soluble dyes are acid, basic, and direct. Chemically, direct and acid dyes are the same as they are both sodium salts of colored acids. Meanwhile, direct dyes have a good affinity to cellulose fiber, high molecular weight, and excellent fastness to light than acid dyes. The fiber readily absorbs direct dyes. An acid dye can only be retained by adding rosin size and alum to fix the dye to the cellulose fiber surface. Basic dye is salts of color bases of low cost and excellent brilliance. It has a strong affinity to lignin and has poor fastness to light. Also, retention aid is needed to fix on the surface of the cellulose fiber. Dry strength additives such as polyacrylamides and starch are used to increase the dry strength of paper through hydrogen bonding. They also act as a retention aid. Dry strength additives such as secondary and hardwood cellulose fiber are frequently used on ­low-​­quality pulp. Wet strength resins like thermoset resins (­formaldehyde, urea formaldehyde) are added to the stock to impart the wet strength of the paper. The wet paper’s tensile strength can increase from 0%–​­5% to 15%–​­50% compared to dry paper. Therefore, the addition of wet strength resin helps reduce the possibility of a wet paper break during the papermaking process. Additionally, the curing process of resin leads to the formation of covalent ­fiber–​­fiber bonds. Special chemicals are some of the other additives that are added for special purpose paper, such as flame retardants and a­ nti-​­tarnish chemicals, which are frequently used in the manufacturing of tissue paper to wrap silverware. Control additives are additives that are added to the stock to improve the papermaking process. These additives do not directly affect the paper properties and do not necessarily retain paper products. Retention aid additives such as polyamines and alum improve the retention of fine, filler, and internal sizing agents. Retention aid molecules are attracted to the fiber surface and are large enough to attract several fibers, fines, and fillers. This results in increased retention and drainage. Drainage aid additives are materials that can increase the drainage rate of water from the pulp stock on the wire. Almost all retention aids are considered to improve the drainage rate as fines and fillers are removed from the white water (­decrease the solid content of white water). They also influence the moisture content (­reduce) of the wet paper (­web) in the press section. Moisture content increases of 1% can reduce the web strength by over 10%. Formation aids like anionic polyacrylamides (­linear polyelectrolytes) promote fiber dispersion, improve web formation, and may allow higher headbox consistency. Defoamer and ­anti-​­foamer are used to control foaming. Foam exists when air or some other insoluble gas is mixed with water containing surfactants (­surface active agents) such as soap and detergent. Defoamer is used to break apart the existing foams, while a­ nti-​­foamer is used to prevent foam formation. Bloides control the growth of microorganisms (­bacteria and fungi) around the paper machine, which produce slime (­consisting of proteins and polysaccharides). Slime may break off in pieces and lead to the pitting of paper, holes, and even the web, which leads to costly downtime.

Papermaking There are several types of papermaking machines including cylinder machine, ­twin-​­wire machine, and Fourdrinier machine. The cylinder machine composes of wire covering the cylinder that is partially submerged in a pulp stock. As the cylinder revolves, the pulp stock is transferred onto the wire and forms a mat. The mat is then detached at the top of the cylinder prior to the pressing process. In the ­twin-​­wire machine, the pulp stock was brought into the gap of the two moving wires. Pressure is applied onto both bottom and top surfaces to remove water. The t­win-​­wire machine is the less used machine in the papermaking industry (­Young et al., 2003). One of the popular papermaking machines is the Fourdrinier machine. The following process in papermaking describes continuous

264

Cellulose

procedures inside the Fourdrinier machine. First, the ready pulp stock is transferred from the pipeline flow and uniformly distributed across the width of the Fourdrinier machine (­headbox) through a connection component known as flow spreader. The headbox is a pressurized device that delivers a uniform jet flow on a forming wire through the slice. A uniform stock distribution is crucial to get good formation and evenly paper. Therefore, the headbox operation is critical for a successful papermaking system. The specific operational objectives of the headbox are as follows:

1. Spreading the stock evenly across the width of the paper machine 2. Leveling out ­cross-​­currents consistency variations 3. Leveling out machine direction velocity gradients 4. Creating controlled turbulence to eliminate flocculation 5. Discharging evenly from the slice opening and impinging the jet onto the forming wire at an appropriate angle and place.

Forming and Dewatering Forming wire is an endless and finely woven belt. The wire acts as a drainage medium and allows fibers and additives to accumulate on it during web forming. The wire travels between two large rolls: the breast roll (­near the headbox) and the couch roll (­near the pressing section). Until the late 1960s, only forming wire made of metal (­usually bronze) was used. Nowadays, plastic fabrics (­polyesters or polyamide filaments) are used because they provide a much longer service life (­up to ten times longer) than metal wire. Various types of forming wire fabrics are produced, and the choice depends on the grades of paper needed. A balance between the filament web (­to reduce wire effect on paper) and drainage rate is necessary for a good web forming. The paper side of the fabric should be smooth, but the machine side is w ­ ear-​­resistant. A breast roll is a firm roll covered with rubber, which supports the forming wire. The other component in the forming section is the forming board, which retards the initial drainage. Drainage retardation helps the formation of a layer of the flat web before drainage. Table rolls are one of the dewatering components in the drainage section located at the lower part of the forming wire before the vacuum box. At high speed, rotating table rolls touching the moving forming wire produce a vacuum at the “­outgoing nip.” This vacuum is responsible for removing water, which helps drainage. However, the vacuum created by the table roll at high speed can ruin the web formation. Therefore, a hydrofoil is introduced below the forming wire to drain some water before the web reaches the table roll. After the table rolls, the web passes through a vacuum box component, which contributes to a more dewatering process from the web. Two types of vacuum boxes are wet and dry vacuum boxes. The dry vacuum box has a higher vacuum strength than the wet vacuum box. The number of vacuum boxes depends on the speed of the paper machine. A dandy roll is another dewatering component used to impart a watermark, help offset flocculation, and smooth out the top side of the web. The dandy roll is on top of the forming wire between the wet and dry vacuum boxes. In cases when a watermark is needed, the design is sewed or welded on the surface roll. It presses into the web on the forming wire. The pressed part in the web will become compact and thin. A couch roll is the last dewatering component in the forming wire part of the papermaking machine. Water is sucked into the couch roll through the suction box inside the roll. It operates at a high vacuum strength of ­40–​­63.5 mmHg. Sometimes, a lump breaker roll is used together with the couch roll to consolidate the web to reduce the probability of breaks during couching and to impact the web and press out any lumps, which might cause breaks in the paper at the press section. Pressing The pressing operation continues the water removal process, which starts from the forming wire part. At this level, the web is relatively permeable to air; therefore, further water removal by vacuum is impractical. The main objectives of pressing are removing water and consolidating the sheet

Overview of Cellulose Fiber as Materials for Paper Production

265

(­compressing the sheet to bring fibers into close contact). The other goals depend on the product’s requirement, like providing surface smoothness, reducing bulk, and promoting higher sheet strength for good runnability in the dryer section. It is more economical to remove water by mechanical means than by evaporation. Water removal should be uniform across the machine, so the pressed sheet has a level moisture profile entering the dryer section. Sheet consolidation is a crucial phase where the fibers are forced into intimate contact, so fi ­ ber-­​­­to-​­fiber bonding develops during drying. If not, the sheet will be bulky. Pressing involves contact between the sheet and the felt in a t­ wo-​­roll press nip. Nip is a contact point between the two rolls where the sheet and felt are pressed. The pressing mechanism inside a nip can be divided into four phases. In phase 1, compression of the sheet and felt begins, which causes air flow out of both structures (­sheet and felt) until the sheet is saturated. No hydraulic pressure is built up and therefore not many changes in dewatering. In phase 2, the sheet is soaked, and hydraulic pressure is built. This causes water to move from the sheet into the felt. As the felt is saturated, water moves out of it through the action of the capillary and the pores between the felt filaments. This phase continues up to the ­mid-​­nip, where total pressure reaches maximum. Water is removed from the sheet, and felt is forced out to the back from the nip through hydraulic pressure. High hydraulic pressure is built in two conditions: if the felt cannot absorb moisture or there is no other way to remove felt from the sheet before reaching the ­mid-​­nip. This will cause crushing to the sheet, where fibers on the surface will stick to the felt. In phase 3, the nip pressure becomes less, and the hydraulic pressure becomes zero as the sheet and felt leave the ­mid-​­nip. This is the maximum point of paper dryness in the nip. In phase 4, both sheet and felt ­re-​­expand, and the sheet becomes unsaturated. A negative hydraulic pressure is created. Since the vacuum in the sheet is higher than the felt, r­ e-​­absorption from the felt to the sheet occurs. The r­ e-​ ­absorption of water in this phase interferes with the pressing process. There are two methods for web transfer from forming wire to press section: open draw or vacuum/­ suction ­pick-​­up. In the open draw, the web is transferred onto felt without contact with the felt from the pressing area. Web tension is needed to pull the web off the forming wire. For a successful web transfer, web tension should be higher than the work required to detach the web from the forming wire. The air blast also separates the web from the forming wire. The open draw is always used for paper machines operating at a speed below 600 m/­min or for the production of heavyweight paper. For the vacuum/­suction ­pick-​­up method, the web is picked up off the forming wire by felt, which wraps a vacuum or suction roll at the point of contact. Drying After pressing, the sheet is conveyed through the drying section, where residual water is removed by evaporation. Water remaining in the web cannot be removed by vacuum or pressing at the drying stage. ­Fiber–​­fiber bonding happens at the drying stage. The dryer section received the wet sheet from the press section at a moisture content between 50% and 65%. The water removal from the sheet continues until the sheet reaches the moisture level required for finishing and converting operations (­4%–​­9%). The drying section is the most expensive part of the papermaking operation (­about 60% of the paper mill energy requirement and 80% of the heat requirement). The sheet is dried by wrapping, including passing through a series of rotating ­stem-​­heated cylinders (­1.­5–​­2.2 m in diameter). A porous fabric (­dryer felt) holds the sheet firmly against the hot surface. The felt also helps control the ­cross-​­machine direction (­CD) shrinkage and keeps the sheet flat. The drying objectives are first to evaporate water as much as possible using a minimum machine. The machine should be designed to reduce energy usage. Second, drying is used to spread the evaporation evenly as possible. Evaporation in CD is the most critical. The variation in moisture at the end of the drying process will affect the sheet quality, such as creeping. The drying ability depends on two factors: the evaporation rate and the steam economy. A high evaporation rate (­water in kg/­h.m2) is needed, but it must be suitable for the grade of the paper wanted. Meanwhile, low steam usage is more economical in terms of steam economy (­energy used per evaporated water, kJ/­ kg). The drying process consists of two fundamental theories: heat transfer and water evaporation.

266

Cellulose

Heat is transferred from steam to the sheet through the cylinder surface of the dryer. Initially, the sheet touches the dryer shell, and the pressure by the felt increases the touching. Water evaporation occurs as the heat transferred to the sheet during connection with the drying cylinder changes the water in the sheet to vapor. Calendering After drying, most paper grades go through arrangements of rolls in calendering section. Calendering is a process where paper passes through nips pressed between rolls under high pressure. The rolls may or may not be of equal hardness. The time taken for pressing the nip is short. The main objectives for calendering are reducing the thickness and obtaining a smooth surface of the paper. It also controls paper density and smoothens the paper watermark. The level of calendering depends on the finishing grade desired. ­Low-​­grade finishing needs the paper to pass through only one or two calendering nips. For high grades, paper may pass through a series of calendering up to 3 sets of rolls, with each set having ­7–​­9 rolls. Calendering operations are carried out ­on-​­machine or ­off-​­machine. For economic reasons and current technology expansions, o­ n-​­machine calendering is used. Calendering under high temperature makes the paper more pliable, and calendaring can be carried out under low pressure. Usually, the first two rolls in the intermediate rolls stack are heated through an inlet of hot water into the rolls. There are two types of calenders: which are machine calenders and supercalenders. The machine calender, also known as a hard nip machine calender, is the most common type used. It is an ­on-​­machine calendering and operates before the reeling process. Paper is pressed between a pair of hard metal rolls and produces paper with the same thickness. Using the recent technology, the ­soft-​­nip machine calender can make paper of uniform density. Meanwhile, a supercalender is an ­off-​­machine with low speed. Calendering is carried out after reeling or winding, or after the paper is coated. A supercalender is a ­multi-​­roller calender composed of alternating hard and soft rolls. Paper is pressed between hard and soft rolls. Soft rolls allow good smoothness without severe blackening of the paper. Reeling and Winding After drying and calendering, paper must be collected at the end of the machine by wrapping it at a metal cylinder called a reel spool crossing the paper machine. This process is called reeling. Reeling is a way of collecting paper from the paper machine. It produces a big paper loop (­full reel). The reeling is performed until it reaches the desired diameter (­full reel). The typical reeling defect is wrinkled and broken due to the air pocket development, especially on dense and low porosity paper grades. After reeling, paper needs to go through the final process called winding. The purpose of winding is to cut and wind the full paper reel into ­suitable-​­sized rolls. During the winding process, the edges of the paper are trimmed off at the slitter section. The broken is conveyed back to the stock preparation section to be recycled. Meanwhile, the middle part of the paper is cut depending on the width desired by customers. Paper of the desired width is rolled on a core made from paper or plastic on the winding drum. Usually, the core is 76 mm in diameter with a wall thickness of about 10 mm. Finally, paper rolls are wrapped with plastic and labeled. Important details often written on the labels include grammage, thickness, type, length, and width of the paper. Then, paper rolls are sent to customers.

CONCLUSION Cellulose is an important component in the papermaking industry that results in greater economic and technical impacts. The abundance of availability and renewable nature of its source make cellulose a suitable precursor for being applied in the papermaking industry. Meanwhile, the recyclable and biodegradable characteristics of cellulose provide added value to the economy.

Overview of Cellulose Fiber as Materials for Paper Production

267

The diverse properties of cellulose fiber from different sources provide the prospect of developing various types of paper and paper products. Future research on increasing the efficiency of cellulose resource utilization for papermaking is still needed to ensure the sustainability of the raw material.

REFERENCES Akgül, M.,  & Tozluoğlu, A. (­2009). Some chemical and morphological properties of juvenile woods from beech (­Fagus Orientalis L.) and pine (­Pinus Nigra A.) plantations. Trends in Applied Sciences Research, 4(­2), 116–​­125. Atalla, R. H., Reiner, R. S., Houtman, C. J., & Springer, E. L. (­2004). PULPING | New technology in pulping and bleaching. In J. Burley (­Ed.), Encyclopedia of Forest Sciences (­­pp. 918–​­924). Oxford: Elsevier. Barberà, L., Pèlach, M. A., Pérez, I., Puig, J., & Mutjé, P. (­2011). Upgrading of hemp core for papermaking purposes by means of organosolv process. Industrial Crops and Products, 34(­1), 865–​­872. Cameron, J. H. (­2004). PULPING | Mechanical pulping. In B. Jeffery (­Ed.), Encyclopedia of Forest Sciences (­­pp. 899–​­904). Massachusetts: Academic Press. Danielewicz, D., & Surma-​­Ślusarska, B. (­2010). Processing of industrial hemp into papermaking pulps intended for bleaching. Fibres & Textiles in Eastern Europe, 18(­6), 110–​­115. Day, A., Chattopadhyay, S. N., & Ghosh, I. N. (­2006). White and coloured handmade paper from jute waste by ambient temperature process. Journal of Indian Pulp and Paper Technical Association, 18(­2), 55–​­58. Dwiky, M. I., Kumala, S. N., Fety, I. R., & Khaliq, F. N. (­2019). The effect of NaOH Concentration variation in the process of paper making from bamboo fiber. IOP Conference Series: Materials Science and Engineering, 535, 012008. Kaur, D., Bhardwaj, N. K., & Lohchab, R. K. (­2018). A study on pulping of rice straw and impact of incorporation of chlorine dioxide during bleaching on pulp properties and effluents characteristics. Journal of Cleaner Production, 170, 174–​­182. Lee, M.-​­K., Kim, J.-​­S., & Yoon, S.-​­L. (­2011). Effective utilization of hemp fiber for pulp and papermaking (­ii)-​­characteristics of hemp-​­wood paper made of hemp fiber cooked at low temperature. Journal of Korea Technical Association of The Pulp Paper Industry, 43(­5), 27–​­33. Małachowska, E., Dubowik, M., Boruszewski, P., Łojewska, J., & Przybysz, P. (­2020). Influence of lignin content in cellulose pulp on paper durability. Scientific Reports, 10(­1), 19998. doi:10.1038/­s41598-​­020-​­77101-​­2. Malik, S., Rana, V., Joshi, G., Gupta, P. K., & Sharma, A. (­2020). Valorization of wheat straw for the paper industry: pre-​­extraction of reducing sugars and its effect on pulping and papermaking properties. ACS Omega, 5(­47), 30704–​­30715. Miao, C., Hui, L.-​­F., Liu, Z., & Tang, X. (­2014). Evaluation of hemp root bast as a new material for papermaking. BioResources, 9(­1), 132–​­142. Mousavi, S. M. M., Hosseini, S. Z., Resalati, H., Mahdavi, S.,  & Garmaroody, E. R. (­2013). Papermaking potential of rapeseed straw, a new agricultural-​­based fiber source. Journal of Cleaner Production, 52, 420–​­424. Sain, M.,  & Fortier, D. (­2002). Flax shives refining, chemical modification and hydrophobisation for paper production. Industrial Crops Products, 15(­1), 1–​­13. Shakhes, J., Zeinaly, F., Marandi, M. A. B., & Saghafi, T. (­2011). The effects of processing variables on the soda and soda-​­aq pulping of kenaf bast fiber. BioResources, 6(­4), 4626–​­4639. Shmulsky, R.,  & Jones, P. D. (­2019). Juvenile Wood, Reaction Wood, and Wood of Branches. In Shmulsky, R., & Jones, P. D. (­eds) Forest Products and Wood Science: An Introduction (­­pp. ­107–​­139). New Jersey: John Wiley & Sons Ltd. Varghese, L. M., Nagpal, R., Singh, A., Mishra, O. P., Bhardwaj, N. K., & Mahajan, R. J. (­2020). Ultrafiltered biopulping strategy for the production of good quality pulp and paper from sugarcane bagasse. Environmental Science Pollution Research, 27(­35), 44614–​­44622. Viikari, L., Suurnäkki, A., Grönqvist, S., Raaska, L., & Ragauskas, A. (­2009). Forest products: biotechnology in pulp and paper processing. In M. Schaechter (­Ed.), Encyclopedia of Microbiology (­3rd ed., ­pp. 80–​­94). Oxford: Academic Press. Young, R. A., Kundrot, R., & Tillman, D. A. (­2003). Pulp and paper. In R. A. Meyers (­Ed.), Encyclopedia of Physical Science and Technology (­Third Edition) (­­pp. 249–​­265). New York: Academic Press.

18

Challenges and State of the Art of Allium Pulp Development for Papermaking A Brief Review Mohammad Harris M. Yahya and Noor Azrimi Umor Universiti Teknologi MARA Cawangan Negeri Sembilan

CONTENTS Introduction..................................................................................................................................... 269 Allium Peels as Raw Pulp for Paper.......................................................................................... 270 Papermaking Technology................................................................................................................ 270 Prospective of Allium Peels as a Paper Pulp................................................................................... 273 Conclusion...................................................................................................................................... 274 References....................................................................................................................................... 274

INTRODUCTION Allium is a genus of onion, scallion, garlic, shallot, leek and chives. It has been used in food preparation for centuries for its aroma and flavor. In addition, due to its extensive nutritional, health and healing properties, Allium is available in the market in many consumable forms, including fresh Allium, Allium extracts, Allium oil, dehydrated macerated oil, black garlic and Allium powder (­Subramanian et al., 2020, Bontempo et al., 2021). The increasing demand and supply of Alliums around the world generate large amounts of waste associated with Allium harvesting and processing, such as damaged cloves, straws, flowers, petioles, stems and leaves (­Fatma and Semia, 2017). Allium peels are one of the collected wastes that have been tested for various purposes (­Nigel et al., 2009; Pereira et al., 2017; Kiassos et al., 2009; Sharma et al., 2016; Thivya et al., 2021; Sha et al., ­ ichalak-​­Majewska et al., 2020; 2013; Gawish et al., 2016; Sara et al., 2021; Poushali et al., 2019; M Poh et al., 2019; Gomaa et al., 2021; Ekemini et al., 2021; Manoj et al., 2022). The paper and board industry is a major contributor to environmental problems, including deforestation and global warming, as virgin wood is the main lignocellulosic material used in paper production. To address this, various n­ on-​­wood fibers such as bagasse, wheat and rice stalks, bamboo and kenaf are being explored and currently used in manufacturing worldwide as a lignocellulosic source for papermaking (­Swarnima et al., 2010; Wael, 2018; Zicheng et al., 2019; Jalal et al., 2010). The ­non-​­wood fibers for papermaking can also be obtained from waste, either from the agriculture or food industry (­Moriam et al., 2021). Although Allium peels are biodegradable wastes, it is still a challenge to manage the wastes without burning or landfilling them. So, it is time to find sustainable ways to use these wastes, and papermaking can be a good option. In this paper, the state of the art for papermaking from Allium peels is discussed. It also discusses the challenges and prospects of the substrate for the paper industry.

DOI: 10.1201/9781003358084-18

269

270

Cellulose

Allium Peels as Raw Pulp for Paper Allium peels can be considered inedible waste from vegetables that are usually discarded or improperly disposed (­Heena and Farida, 2020). In the European Union, more than half a million tons of allium waste are discarded every year (­Vanesa et al., 2011). While in Asian countries such as Japan, more than 144,000 tons of Allium waste are produced annually (­Feridoun et al., 2013). In previous work, Allium cepa peel waste was studied for papermaking, and it was found that the cooking time plays an important role in determining the strength of the paper sheet, with an increase in the cooking time from 120 to 180 min increasing the tensile and tear strength of the paper sheet (­Mohammad et al., 2020). Moreover, Allium sativum (­garlic) peel alone has 37.2% of cellulose, which is comparable to wheat straw, jute stick (­Taslima et al., 2021), dried durian peel fiber (­Shaiful et al., 2016), cassava peel (­Aripin et al., 2013), red lentil stalks (­Taslima et al., 2021) and rapeseed straw (­Hosseinpour et al., 2010) where they were 37%, 37.7%, 35.6%, 37.9%, 36.5% and 36.6%, respectively (­see ­Table 18.1). Shakles (­2011) stated that the suitable cellulose composition in plant materials for pulp production in papermaking is 34% and above. Although the amount of cellulose is lower than that of the commercially used hardwood cellulose (­42.5%), the lignin content of 9.96% is still the lowest among other ­non-​­wood fibers and hardwood fibers. Lignin is an undesirable polymer and can affect the reaction times of delignification in the digester or the consumption of pulp chemicals. The lower the lignin content in the component, the shorter the digestion times and chemical consumption. The use of Allium peels as paper pulp has some additional advantages and some disadvantages. For example: i. Allium peels can be obtained as abundant agricultural or food industry waste. Their volume is so large and the cost of obtaining the peels is low to ­non-​­existent that they contribute to supporting SDG12 (­Luis et al., 2020). ii. They can be easily recycled because a simple cleaning process does not harm the existing flora, thus preserving a large portion of the perennial biomass. iii. Since Allium peels play a major role in paper production, it helps reduce the problem of open burning or landfills that cause air pollution, thus supporting SDG15 (­Luis et  al., 2020). iv. Focusing on papermaking, the difficult points for Allium peels are the removal of pigments and water: bleaching and drying; production and energy costs related to pilot or l­ arge-​­scale production (­not yet tested), financing and market value. Paper made from pure Allium peel fibers could suffer from weak bursting, tearing and folding strength. Therefore, blending Allium peel pulp with other raw materials such as softwood fibers must be used to improve paper properties (­comparable to kraft paper).

PAPERMAKING TECHNOLOGY In papermaking, a dilute suspension consisting largely of separate and individual cellulose fibers in water is dewatered through a ­sieve-​­like screen to produce a mat of randomly interwoven fibers. Water is removed from this sheet by pressing, sometimes with the aid of suction or vacuum, or by heating. A traditional handmade papermaking process can be applied to hardwood or ­non-​­wood cellulose, such as Allium husks, to produce paper sheets. This technique uses maximum water as the main medium and tends to create a hydrogen bond between the fibers in the paper sheet. ­Figure  18.1 provides an overview of the papermaking process from Allium (­Allium sativum) peels. The papermaking process begins with the preparation of fibers suitable for papermaking. The fibers are cooked in a digester at a controlled temperature, pressure and time. The fibers are added to the digester with chemicals such as sodium hydroxide or organic solvents. This is done to help the delignification process of the fibers. It takes about 3 h (­180 min) and 170°C for the fibers to be fully

Cellulose Hemicellulose Lignin

Fiber/­Components (%)

37.22 35.21 9.96

Allium sativum L. Peels (­Present Study) 35.60 18.60 10.70

Dried Durian Peel Fiber (­Shaiful et al., 2015) 37.90 37.00 7.50

Cassava Peels (­Aripin et al., 2013)

­TABLE 18.1 Comparison of the Chemical Composition of Various Sources of Pulp

36.60 40.90 20.00

Canola Straw (­Hosseinpour et al., 2010) 37 28.6 25.1

Wheat Straw (­Taslima et al., 2021)

37.7 31.5 27.1

Jute Stick (­Taslima et al., 2021)

36.5 22.7 23.8

Red Lentil Stalks (­Taslima et al., 2021)

­38–​­49 Not available ­23–​­30

Hardwooods (­Mazhari Mousavi et al., 2013)

Challenges of Allium Pulp Development for Papermaking 271

272

Cellulose

Fiber selection (Cleaning and drying)

Cooking of the fiber (Digester at 170C ).

Washing the cooked fiber under tap water until obtaining the cellulose pulp.

Paper sheet making

Pressing and drying (Remove excessive water)

Drying prior to forming a paper sheet.

­FIGURE 18.1  Papermaking process using Allium peels (­Allium sativum).

­FIGURE 18.2 

Allium sativum fiber after undergoing fractionation.

cooked. The stove can be in a rotating form or the liquid in the stove is circulated with extreme air to ensure even distribution of the delignification chemicals in the fibers in the stove. After complete cooking, the black liquor in the digester must be removed, and the cellulose, which was already turned into a slurry form, is then washed under tap water until it is completely free of the black liquor. The clean slurried fibers are then fed to a fractionator. The fibers are separated into a uniform size of about 0.05 mm using a water medium, mechanical vibration and a standard slot size to filter the standard size of fibers. The fine fibers with a size of 0.05 mm or less pass through the slot and are collected over a single jersey mesh. F ­ igure 18.2 shows the filtered pulp after passing through the fractionator. The pulp is then weighed based on the moisture content of the fibers and shredded

Challenges of Allium Pulp Development for Papermaking

­FIGURE 18.3 

273

Allium sativum L. paper sheet.

in the disintegrator at 3,000 rpm for 3 min to break the fiber bundle into individual fibers. Then, the broken fibers together with water are poured into the ­semi-​­automatic sheet machine to turn the pulp into a sheet of paper. The Allium paper sheet is then pressed on both sides, front and back, for 5 min and 3 min respectively. In this way, the excess water is squeezed out of the sheet while confirming the uniform thickness of the paper sheet. Finally, the paper sheet is dried at room temperature with a standard weight on the edge to prevent the paper sheet from curling or rippling during the drying process. ­Figure 18.3 shows the Allium sativum paper sheet produced.

PROSPECTIVE OF ALLIUM PEELS AS A PAPER PULP Although the peels are easy and plentiful to obtain, some aspects of the challenges of processing them into a paper sheet must be considered. The first challenge in using Allium sativum is cleaning the peels before they are used in the cooking process. The peels are very light and thin (­they just float in water and are difficult to submerge for a good cleaning process) and have spots of rotten color, so lots of clean water and a special technique (­not yet discovered) are needed to ensure that the peels are white in color and free of impurities. The adhering impurities could interfere with the reaction between the fibers and the chemical in the digester. This might be due to the foreign elements existing that appeared as a colored spot in the solution bath. In addition, the impurities are likely to vary the chemical composition results, making it difficult to determine the exact range of chemical composition in the end. The fiber yield of Allium sativum is another challenge because a large number of peels are needed to obtain a large amount of yield for papermaking. An optimum chemical concentration of about 20% sodium hydroxide is required for chemical pulping in the digester to achieve an overall pulp yield of 37.22%. A lower or higher sodium concentration results in a lower pulp yield because the fibers are more prominent or completely dissolved in the solvent chemical. On the other hand, consumer perception and behavior to properly store valuable wastes is another challenge to ensure

274

Cellulose

that the wastes can still be recovered under fresh conditions before they become contaminated. Systematic storage of the waste could increase the volume of fresh waste peel fibers for the following process (­Al Seadi and ­Holm-​­Nielsen, 2004; Kondusamy et al., 2022). Therefore, another challenge in the use of Allium sativum peel waste for papermaking is the specific storage of this waste to ensure the quality of the waste, or it can be used for other types of recyclables to increase economic efficiency (­Richa et al., 2022; Sharma and Garg, 2019). The use of pure Allium sativum for papermaking affects the physical and mechanical performance for some time. It is not able to achieve excellent tensile, tear and burst strength alone. To improve the mechanical properties of Allium sativum paper, blending with other fibers, such as other ­wood-​­free filament fibers or recycled pulp from waste paper, is suggested. Other additional chemical treatments of Allium sativum peels, such as organic solvents, are proposed to increase the strength of the individual fibers to strengthen the bond between the fibers in the paper sheet. Another challenge in treating the fibers is the selection of appropriate chemical solvents and their suitable concentration to avoid overtreating the fibers and damaging the chemical and physical structure of the fibers (­has not been researched yet). In addition, the machine for plucking the peels of Allium sativum is available in many designs and methods (­Umesha et al., 2011), but still, a small amount of flesh of Allium sativum can be obtained in the container with the separated waste peels, and it must be completely filtered and separated from the peels to avoid problems during the cooking process. The pulp contains a different chemical composition than the peels and could affect the pulp quality and the physical and mechanical properties of the paper. All the predicted problems and challenges are very important to establish proper management of processing waste, especially Allium sativum peels, into paper sheets. Proper management, starting with waste storage, sorting out impurities, cleaning and drying, a special cooking process including the use of chemical solvents and the development of special treatment or other additional fibers with the Allium sativum peels, could contribute to another source of income for the small food industry by introducing other product innovations instead of food.

CONCLUSION The Allium peels, especially Allium sativum, have a cellulose content of 37.22% suitable for papermaking. Although the cellulose content is still lower compared to commercial hardwood cellulose for papermaking, the lignin content of 9.96% is still much lower than hardwood and most n­ on-​­wood fibers such as canola straw, cassava peels and dried durian peels. A simple papermaking process can be applied to produce paper from these wastes, thus maximizing the use of waste to achieve ­zero-​­waste production in the industry. Proper waste management or storage system, especially for the Allium peels, is one of the challenges really needed to ensure fresh waste in abundant volume available for papermaking or other applications. It is proposed that in commercial papermaking, a blended fiber composed of Allium peels and other fibers such as recycled paper can be mass produce. The use of blended fiber for pulp production can ensure better physical and mechanical properties of the paper sheet.

REFERENCES Al Seadi, T., & Holm-​­Nielsen, J.B. (­2004). III.2-​­Agricultural wastes. Waste Management Series, 4, 207–​­215. Aripin A. M., Mohd Kassim A. S., Daud Z., & Mohd Hatta M. Z. (­2013). Cassava peels for alternative fibre in pulp and paper industry: Chemical properties and morphology characterization. International Journal of Integrated Engineering, 5(­1), 30–​­33. Bontempo, P., Stiuso, P., Lama, S., Napolitano, A., Piacente, S., Altucci, L., Molinari, A.M., De Masi, L., & Rigano, D. (­2021). Metabolite profile and in vitro beneficial effects of black garlic (­allium sativum L.) polar extract. Nutrients, 13, 2771.

Challenges of Allium Pulp Development for Papermaking

275

Ekemini I., Lin Y., Ambrish S., & Ruiyun L. (­2021). Chemical modification of waste Allium cepa peels to Cu-​ c­ omplex composite and application as eco environmental oilfield anticorrosion additive. Journal of King Saud ­University -​­Engineering Sciences, 33(­6), 375–​­385. Fatma, K.,  & Semia, E. C. (­2017). Perspective of garlic processing wastes as low-​­cost substrates for production of high-​­added value products: A review. Environmental Progress & Sustainable Energy, 36(­6), ­1765–​­1777. Feridoun, S., Somayeh, D., Jalal, A., & Koji F. (­2013). Adding value to onion (­Allium cepa L.) waste by subcritical water treatment. Fuel Processing Technology, 112, 86–​­92. Gawish, S. M., Helmy, H. M., Ramadan, A. N., Farouk, R., & Mashaly, H. M. (­2016). UV Protection properties of cotton, wool, silk and nylon fabrics dyed with red onion peel, madder and chamomile extracts. Journal of Textile Science & Engineering, 6(­4), 1–​­13. Gomaa, A. M. A., Supriya, S., Kwok, F. C., Essam R. S., Algarni, H., & Gurumurthy Hegde T. M. (­2021). Superior supercapacitance behavior of oxygen self-​­doped carbon nanospheres: A conversion of Allium cepa peel to energy storage system. Biomass Conversion and Biorefinery, 11, 1311–​­1323. Heena, S. K., & Farida, P. M. (­2020). ADMET analysis of phyto-​­components of Syzygium cumini seeds and Allium cepa peels. Future Journal of Pharmaceutical Sciences, 6(­117), 1–​­9. Hosseinpour, R., Fatehi, P., Ahmad Jahan, L., Yonghao, N., & Javad, S.S. (­2010). Canola straw hemimechenical pulping for pulp and paper production. Bioresource Technology, 101, 4193–​­4197. Jalal, S., Mohamma, R. D. F., Pejman, R. C., & Farhad, Z. (­2010). Evaluation of harvesting time effects and cultivars of Kenaf on papermaking. Bioresources, 5(­2), 1268–​­1280. Kiassos, E., Mylonaki, S., Makris, D. P., & Kefalas, P. (­2009). Implementation of response surface methodology to optimise extraction of onion (­Allium cepa) solid waste phenolics. Innovative Food Science  & Emerging Technologies, 10(­2), 246–​­252. Kondusamy, D., Tharun, K., Mani, K.,  & Sandeep, K. M. (­2022). ­Chapter  11-​­Techno-​­economic feasibility and hurdles on agricultural waste management. In Hussain, C. M., Singh, S., & Goswami, L (­eds) Emerging Trends to Approaching Zero Waste Environmental and Social Perspectives, 243–​­264. Elsevier, Amsterdam. Luis, M. F., José, P. D.,  & Alina, M. D. (­2020). Mapping the sustainable development goals relationships. Sustainability, 12(­3359), 1–​­16. Manoj, K., Mrunal, D. B., Muzaffa, r H., Sneh, P., Sangram, D., Radha, Nadeem R., Deepak C., R. Pandiselvam, Anjineyulu, K., Maharishi, T., Varsha S., Marisennayya, S., T. Anitha, Abhijit, D., Ali A.S.Sayed Farouk, M., Gadallah Ryszard, A., & Mohamed, M. (­2022). Onion (­Allium cepa L.) peels: A review on bioactive compounds and biomedical activities, Biomedicine & Pharmacotherapy, 146, 112498. Mazhari Mousavi, S. M., Hosseini, S. Z., Resalati, H., Mahdavi, S., & Garmaroody, E. R. (­2013). Papermaking potential of rapeseed straw, a new a­ gricultural-​­based fiber source. Journal of Cleaner Production, 52, ­420–​­424 Michalak-​­Majewska, M., Teterycz, D., Muszyński, S., Radzki, W., Sykut, & Domańska, E. (­2020). Influence of onion skin powder on nutritional and quality attributes of wheat pasta. PLoS ONE, 15(­1), e0227942. Mohammad, H. M. Y., Mohd R. A., & Normala H. (­2020). Characteristics and mechanical properties of thin paper sheets made from onion peels (­allium cepa). Journal of Academia, 8(­2), 15–​­21. Moriam, D. A., Abdulazeez, T. L., Abibat, O. J., Alabi, K. A., Owolabi, O. O., Nelly A. N., Taofeek S., & Sheriff A. (­2021). Fascinating physical-​­chemical properties and fiber morphology of selected waste plant leaves as potential pulp and paper making agents. Biomass Conversion and Biorefinery, 11, 3061–​­3070. Nigel, C. S., Partington, S. M., & Towns, A. D. (­2009). Industrial organic photochromic dyes, society of dyers and colourists. Coloration Technology, 125, 249–​­261. Pereira, G. S., Cipriani, M., Wisbeck, E., Souza, O., Strapazzon, J. O., & Gern R. M. M. (­2017). Onion juice waste for production of Pleurotus sajor-​­caju and pectinases. Food and Bioproducts Processing, 106, 11–​­18. Poh, W. C., Poh, S. C., Mohd, H. A., Siti Aisha, M. R., Fu, S. J. Y., & Su-​­Yin K. (­2019). Water Extract of onion peel ash: An efficient green catalytic system for the synthesis of isoindoline-​­1,3-​­dione derivatives. Malaysian Journal of Analytical Sciences, 23(­1) 23–​­30. Poushali, D., Sayan, G., Priti, P. M., Hemant, K. S., Madhuparna, B., Santanu, D., Sharba, B., Amit, K. D., Susanta, B., & Narayan C. D. (­2019). Converting waste Allium sativum peel to nitrogen and sulphur co-​ d­ oped photoluminescence carbon dots for solar conversion, cell labeling, and photobleaching diligences: A path from discarded waste to value-​­added products. Journal of Photochemistry and Photobiology B: Biology, 197, 111545.

276

Cellulose

Richa, G., Anamika, K., Dushyant, D., & Niva, R. M. (­2022). ­Chapter 10-​­Waste management in fashion and textile industry: Recent advances and trends, life-​­cycle assessment, and circular economy. In Hussain, C. M., Singh, S., & Goswami, L (­eds) Emerging Trends to Approaching Zero Waste Environmental and Social Perspectives, 215–​­242. Elsevier, Amsterdam. Sara, P.-​­R., David, S., Cinthia, A., Tanya, T., Nartzislav, P., Daniela, P., & María, J. L. (­2021). Biomass waste-​ ­derived nitrogen and iron co-​­doped nanoporous carbons as electrocatalysts for the oxygen reduction reaction. Electrochimica Acta, 387, 138490. Sha, L., Xueyi, G., & Qinghua, T. (­2013). Adsorption of Pb2+, Cu2+ and Ni2+ from aqueous solutions by novel garlic peel adsorbent. Desalination and Water Treatment, 51, 7166–​­7171. Shaiful, R. M., Mohd Halim, I. I., Sharmiza, A., Muhammad Syauqi, A., Ahmad, T., Radhi, A. R., Siti Nurul Aqma, A. R., & Siti Nur Faeza M. Z. (­2016). Characteristics of linerboard and corrugated medium paper made from durian rinds chemi-​­mechanical pulp. MATEC Web of Conferences, 51(­02007), 1–​­10. Shakles, J., Marandi, M.A.B., Zeinaly, F., Saraian, A., & Saghafi, T. (­2011). Tobacco residuals as promising lignocellulosic materials for pulp and paper industry. Bioresources, 6(­4), 4481–​­4493. Sharma, K., & Garg, V. K. (­2019). ­Chapter 10-​­Vermicomposting of waste: A zero-​­waste approach for waste management. In Taherzadeh, M., Bolton, K., Wong, J., & Pandey, A (­eds) Sustainable Resource Recovery and Zero Waste Approaches, 133–​­164. Elsevier, Amsterdam. Sharma, K., Mahato, N., Nile, S. H., Lee, E. T., & Lee, Y. R. (­2016). Economical and environmentally-​­friendly approaches for usage of onion (­Allium cepa L.) waste. Food & Function, 7, 3354–​­3369. Subramanian, M.S., Nandagopal, G.M.S., Nordin, S.A., Thilakavathy, K.,  & Joseph, N. (­2020). Prevailing knowledge on the bioavailability and biological activities of Sulphur compounds from Alliums: A potential drug candidate. Molecules, 25, 4111. Swarnima, A., Dharm, D., & Tyagi, C. H. (­2010). Complete Characterization of bagasse of early species of saccharum officinerum-​­co 89003 for pulp and paper making, BioResources, 5(­2), 1–​­18. Taslima, F., Yonghao, N., Mohammad, A. Q., Mohammad, N. U., & Md Sarwar, J. (­2021). Non-​­wood fibers: Relationships of fiber properties with pulp properties. ACS OMEGA, ACS Publications, 6, 21613−21622. Thivya, P., Bhosale, Y. K., Anandakumar, S., Hema, V.,  & Sinija, V. R. (­2021). Exploring the effective utilization of shallot stalk waste and tamarind seed for packaging film preparation. Waste and Biomass Valorization, 12, 5779–​­5794. Umesha, Prakasha, T. L., Mandhar, S. C., Rajasekharppa, K. S., & Venkatachalapathy, K. (­2011). Evaluation of garlic (­Allium sativum L.) peeling methods. Environment and Ecology, 29(­1A), 316–​­318. Vanesa, B., Esperanza, M., María, A. M.-​­C., Yolanda, A., Francisco, J. L.-​­A., Katherine, C., Leon, A. T., & Rosa, M. E. (­2011). Characterization of industrial onion wastes (­allium cepa L.): Dietary fibre and bioactive compounds. Plant Foods for Human Nutrition, 66, 48–​­57. Wael, A. E. (­2018). Rice straw as a raw material for pulp and paper production. Encyclopedia of Renewable and Sustainable Materials, ­296–​­304. Elsevier, Amsterdam. Zicheng, C., Huiwen, Z., Zhibin, H., Lanhe, Z., Xiaopeng, Y. (­2019). Bamboo as an emerging resource for worldwide pulping and papermaking. Bamboo for Pulp & Paper, 14(­1), 3–​­5.

19

Application of Cellulose in Leather Victória Vieira Kopp, Vânia Queiroz, Mariliz Gutterres, and João Henrique Zimnoch dos Santos Federal University of Rio Grande do Sul

CONTENTS Introduction..................................................................................................................................... 277 Leather Processing.......................................................................................................................... 278 Beamhouse................................................................................................................................. 278 Tanning....................................................................................................................................... 278 Finishing..................................................................................................................................... 278 Tanning.................................................................................................................................. 279 Retanning.............................................................................................................................. 279 Finishing................................................................................................................................ 279 Leather Solid Wastes.............................................................................................................280 Application of Cellulose in Leather Processing..............................................................................280 Cellulose in Tanning...................................................................................................................280 Cellulose in Retanning............................................................................................................... 281 Cellulose in Finishing................................................................................................................ 281 Composites of Cellulose and Solid Leather Waste......................................................................... 282 Conclusion...................................................................................................................................... 283 References.......................................................................................................................................284

INTRODUCTION Leather is a product with a high commercial value. There is a great demand for leather goods, including footwear, clothing, furniture, automotive upholstery (­Winter et al., 2015), as well as membranes and shielding materials (­Jiang et al., 2020). In 2020, the global leather goods market was valued at USD 394.12 billion and is expected to grow from 2021 to 2028 with a compound annual growth rate of 5.9%. It is expected that the increasing demand for comfortable, trendy, and fancy leather apparel, footwear, and accessories, along with growing brand awareness, has a positive impact on the market, according to Grand View Research (­2020). Hides or skin are converted into leather by the leather industry. The classic processing of leather production uses limited and nonrenewable resources, such as chrome (­Ding et al., 2019). Cellulose in turn is one of the most abundant sustainable and renewable biomasses on the planet. It is a tough, fibrous, ­water-​­insoluble polysaccharide that is important in maintaining the structure of plant cell walls. It is usually synthesized by plants (­Brigham, 2018; Jiang et al., 2020). It has several applications, including the potential to be used in the processing of leather in the tanning, retanning, and finishing stages. The leather industry generates tons of solid waste every year, which is mainly produced during the operation of adjusting the thickness of the leather or lowering it. For each ton of rawhide processed, approximately 100 to 150 kg of shaving is produced. It is estimated that approximately 0.8 million tons of chromium shavings are generated globally each year (­Steffanello Piccin and DOI: 10.1201/9781003358084-19

277

278

Cellulose

Gutterres, 2019; Agustini and Gutterres, 2017). Due to their composition, these wastes can be a source of raw materials for several products. When cellulose is added, composites are developed.

LEATHER PROCESSING The conversion of skin or hide into leather requires several processing steps that involve complex chemical reactions and mechanical processes (­Gutterres and Mella, 2015). The aim is to achieve a final leather product with the desired stability, appearance, water and temperature resistance, elasticity, perspiration, and air permeability (­Selvaraju et al., 2019). The fabrication of leather requires various chemicals, such as chromium, vegetable tannins, and polymer resins, including cellulose, and involves many steps. The three main phases of leather processing are beamhouse, tanning, and finishing (­Hansen et al., 2020). The leather processing steps and their purposes are as follows (­Gutterres and Mella, 2015; Kopp et al. 2021):

Beamhouse • Reception: receiving the natural or salted hide (­preserved to avoid its decomposition); • Salt ­shake-​­off: mechanically removes salt from the hide; • Presoaking: replenishing part of the water content to the hides that has been removed (­dehydration) during conservation; • Prefleshing: removing the subcutaneous tissue of the hide using a stripping machine; • Soaking: reporting the original water content of the hides; • Dehairing and liming: removing the epidermis along with hair and other keratinous hide materials. Lime is added to swell, loosen, and open the fibrous structure, and sulfide is usually applied to degrade the hair; • Fleshing: eliminating the remaining subcutaneous waste; • Splitting: dividing the hide into two layers; • Deliming: eliminating lime, reverse swelling, and adjusting pH for bating; • Bating: an enzymatic step that removes the residues of the epidermis and keratin; • Pickling: interrupting enzymatic activity, acidifying the hide in the presence of salt, conditioning it for tanning.

Tanning • Tanning: designation of the hide treatment used to obtain leather resistant to microbial attack with chemical, thermal, and physical transformation: ­wet-​­blue leather (­­chrome-​ ­tanned) and ­vegetable-​­tanned leather (­vegetable tannin);

Finishing • • • • • • • •

Samming and shaving: adjusting and standardizing the thickness of the part; Deacidification: adjusting the pH to neutralize the acidity present; Retanning: giving specific texture and ­physical–​­mechanical characteristics; Dyeing: giving color; Fatliquoring: lubricating the fibers and giving softness to the leather; Drying: removing water; Prefinishing: preparing the leather and surface for finishing; Finishing: treating the surface to obtain the desired properties and appearance of the final leather.

Cellulose can be applied to the leather during the following three different processing steps: tanning, retanning, and finishing. These steps will be better explained in the following sections.

Application of Cellulose in Leather

279

Tanning Tanning is the process that bonds tanning substances to the collagen fiber structure of hide/­skin, mostly by collagen protein c­ross-​­linkage. The tanning process provides putrefaction stability (­microbial and enzymatic), chemical stability, and hydrothermal stability to the hide (­Gutterres and Mella, 2015). Reactions of ­cross-​­linking occur between the tanning agent and the collagen matrix, in the active ­groups –​­NH2 ­and –​­COOH. The hydrothermal stability of leather is measured by the shrinkage temperature (­Ts), which denotes the ­cross-​­linking degree of collagen fibers (­Li et  al., 2019). The reaction between the tanning agent and hide collagen fiber contributes to the enhancement of Ts, and a higher Ts represents a better tanning effect. ­Chrome-​­tanned leather has a Ts above 100°C (­Ding et al., 2019). Mineral salts, such as chromium, aluminum, titanium, iron, and zirconium salts, are used as tanning agents because they have a favorable tanning effect and are widely available (­Jiang et al., 2020). Chrome salt is currently the most prevalent tanning agent used in leather production because of the favorable properties of the resulting leather. However, as a limited and nonrenewable resource, the permanent use of chrome salt in tanning, in addition to its traditional use as a cleaning agent, may lead to resource depletion and environmental pollution issues. This means that developing other tanning materials that have a favorable tanning effect and are versatile is essential and will be good for the sustainable development of the leather industry (­Ding et al., 2019). Examples of alternative tanning agents have been proposed in the literature, such as tetrakis(­hydroxymethyl)­phosphonium sulfate and commercial Laponite clay (­Shi et al., 2019) and graphene oxide (­Lv et al., 2016). Retanning Retanning determines the leather’s desired level of fullness, softness, and grain properties. These properties can be attained by using p­ henol–​­formaldehyde resins, acrylic resins, and protein fillers (­Selvaraju et al., 2019). P ­ ost-​­tanning, the most significant inorganic pollution load (­due mainly to chlorides and sulfates) in wastewater comes from natural and synthetic retanning agents (­Hansen et  al., 2020). In addition, they are difficult to degrade naturally or treat in wastewater treatment plants (­Selvaraju et al., 2019). There is a new class of retanning agents that uses biopolymers to create ­better-​­quality leather products. This new range of materials consists of products that are compatible with these traditional retanning agents based on renewable raw materials such as carbohydrates, proteins, protein hydrolysates (­PHs), and biopolymers. Such biobased materials are expected to increase the economic feasibility of retanning agents (­Selvaraju et al., 2019), such as cellulose. Finishing Leather finishing is the final manufacturing process and comprises a set of treatment steps that are performed to give the appropriate/­desired appearance and properties for the final leather article. During the finishing process, surface defects are corrected, thus improving the quality of the leather and its color, fullness, elasticity, shine, solidity, and stability (­Winter et al., 2018; Tamilselvi et al., 2019). Finishing involves successive stages of applying various chemical product formulations, followed or interspersed by drying operations and mechanical operations such as pressing, polishing, and drumming. The successive applications are called impregnation, stucco, prebottom, bottom, topcoat, middle topcoat, final topcoat, and feel modifiers. Depending on the required characteristics of the final product, these steps may or may not all be present. The binder products used are normally softer in the lower layers and increase in hardness until reaching the top layers. The quality and characteristics of the finish depend on the intermediate drying of the layers that must be performed after each layer is applied (­Winter, 2014). To know if the finishing process is effective, various physical tests for flexing endurance, adhesion of finish, light fastness, dry and wet rubbing fastness, and heat fastness properties can be performed (­Gumel and Dambatta, 2013; Tamilselvi et al., 2019).

280

Cellulose

Currently, the most common leather finishing agents include polyacrylates, polyurethanes, nitrocellulose, and caseins (­Maina et al., 2019; Gumel and Dambatta, 2013; Zhang, 2021). Nitrocellulose is widely used in leather topcoats because it can produce a good clear finishing film on leather through a simple process (­without any fixation), and the film is waterproof, washable, easy to clean, very fast to rub, and mechanically resistant to stress, with a­ nti-​­fouling characteristics (­Gumel and Dambatta, 2013). Leather Solid Wastes During leather processing, a substantial amount of solid waste is generated that impacts the environment. However, these wastes can be utilized as raw materials to produce valuable products. Many wastes come from the beamhouse, such as hide residues, from tanning, such as chromed leather waste, and from finishing, such as buffing dust. Solid leather waste is a protein source that can be used to develop composites with cellulose.

APPLICATION OF CELLULOSE IN LEATHER PROCESSING Cellulose in Tanning Cellulose can be used as a tanning agent, as a masking ligand to aid in the penetration of metals into the hide matrix, or can be modified to produce aldehyde groups (­Jiang et al., 2020). The strong reaction between the metal, such as aluminum, and the collagen fibers leads to metal overcharge on the leather surface and then a weak tanning effect. To overcome this problem, Jiang et al. (­2020) developed a tanning agent with A ­ l-​­oligosaccharide complexes synthesized via AlCl3-​­catalyzed cellulose depolymerization. AlCl3 is the catalyst for cellulose degradation, and it also plays a role in tanning by coordinating metal ions. The Al3+ reacts with the hydroxyl groups of the oligosaccharides and promotes the decolorization of the leather, also enabling the penetration of Al into the collagen matrix of the skin. Thereafter, the Al species are free from the ­Al-​­oligosaccharide and coordinate with ­the -​­NH2 group of collagen fibers of the leather, contributing to the stabilization of the fiber bundle and to a realization of satisfactory tanning performance. H ­ igh-​­purity tanning agents were produced by liquid‒liquid extraction with tetrahydrofuran as the solvent to remove small, oxygenated substances and ­high-­​­­molecular-​­weight oligosaccharides decomposed by cellulose. The novel tanning agent achieved a leather Ts close to 80°C (­Jiang et al., 2020). However, the tanning ability of this ­Al-​­oligosaccharide tanning agent is not sufficient for commercial use, limiting its potential due to the inferior tanning performance of Al species. The general Ts requirement for commercial use is that the temperature must be above 80°C (­Jiang et al., 2021). Jiang et al. (­2021) developed an A ­ l–­​­­Zr-​­oligosaccharide complex. The conversion of cellulose used a biphasic solvent system, using AlCl3-­​­­NaCl-​­H2O as a catalytic reaction phase and γ-​­valerolactone as an in situ extraction phase, through a stepwise degradation and oxidation process to produce a ­high-​­quality ­oligosaccharide-​­based masking agent. The oligosaccharides were oxidized to give active coordination groups, which would help mask the penetration of metal ions. Zr and Al are two different types of metals that can form strong ­cross-​­links when combined. This makes them ideal for improving the performance of tanned leather. This product is appropriate for commercial applications at 85.2°C (­Jiang et al., 2021). Ding et al. (­2019) prepared a ­polysaccharide-​­based tanning agent with ­peroxide–​­periodate commodification of carboxymethyl cellulose (­CMC). CMC is a commercially available biomass derived from cellulose. It is a popular choice for energy sources due to its high energy density and low cost. Sodium carboxymethyl cellulose (­­Na-​­CMC) was first predegraded with H2O2 assisted by a ­Cu–​­Fe catalyst to reduce the viscosity of CMC. This was then proceeded by periodate oxidation to produce high solid dialdehyde carboxymethyl cellulose (­DCMC), where the aldehyde groups give the chemical structure of DCMC for leather tanning, reaching a Ts of 85°C. The fiber dispersion of ­DCMC-​­tanned leather was comparable to that of ­Cr-​­tanned leather. ­DCMC-​­tanned leather had

Application of Cellulose in Leather

281

physical and organoleptic properties, such as tensile strength, tear strength, burst strength, compressive resilience performance, and softness, comparable to those of ­chrome-​­tanned leather. However, formaldehyde was detected in DCMC products. The World Health Organization has identified formaldehyde as a carcinogenic and teratogenic substance. Therefore, the formaldehyde tenor in leather is severely controlled by regulations and standards to maintain the safety of leather products. DCMC is supposed to be formaldehyde free due the aldehyde groups located on the polysaccharide chain of DCMC. However, it is possible to reduce the formaldehyde content in DCMC by lowering the degradation rate and raising the rate of substitution of CMC (­Yi et al., 2020).

Cellulose in Retanning After tanning, leather is often treated with various auxiliary substances to improve its physical and aesthetic properties. Hence, Selvaraju et al. (­2019) used biocomposites made from natural and biological sources developed to replace these unfavorable adjuvants. The biocomposite was prepared with cellulose (­acting as a synthetic tanning agent), soybean oil, and a bioemulsifier termed emulsan (­acting as a fatliquor) for the leather ­post-​­tanning process, which served as a simultaneous ­retanning–​­fatliquoring agent. Biocomposites were prepared through ultrasonication by blending different amounts of microcrystalline cellulose with soybean oil and a constant concentration of emulsan prepared from the bacterial strain Acinetobacter calcoaceticus. The value of an example composite for use in leather after tanning was evaluated by using it as a retanning agent. Composites containing mostly encapsulated cellulose and soybean oil have been found to penetrate the fiber structure of the leather matrix due to their excellent emulsifying properties. A composite material of emulsified soybean oil containing cellulose was well dispersed in an emulsifier, which serves to fill the pores of the leather and give a great deal of elongation. Fuller leather was found to achieve better retanning than the control leather, demonstrating a better restoration effect. Leathers treated with a biopolymeric composite showed improved strength and physical properties, such as tensile strength, elongation at break, grain crack strength, and tear strength, compared to control leathers. The leather treated with a biopolymeric composite had better properties than the leather made with standard agents.

Cellulose in Finishing Many changes have been made to the leather finishing process as a result of the search for better quality and more efficient use of the finish applied. The changes in technology and development have led to the use of ­water-​­based lacquers (­which use less solvent) instead of organic lacquers (­which use more solvent). Some types of paints, sealants, adhesives, and plastics are made from acrylics, urethanes, butadiene rubber, vinyl resins, and so on. The ultimate purpose of these resins is to bind pigment molecules, adhere to the skin, impart elasticity so that the final layer of leather can be tightened, and protect the leather surface (­Gumel and Dambatta, 2013). Tamilselvi and collaborators (­2019) extracted cellulose from peanut husks and sugarcane bagasse for use in leather finishing. The composition of peanut husk and bagasse is mostly cellulose, hemicellulose, which makes these wastes viable raw materials for cellulose. Extraction was performed by modified acid hydrolysis. The spray cellulose gave fullness to the final leather without affecting its aesthetic properties. To improve the solubility of cellulose acetate and increase its use in leather finishing, a s­elf-​ ­emulsifying aqueous emulsion was synthesized using cellulose diacetate, dimethylolbutyric acid, and hexamethylene diisocyanate. Cellulose acetate is produced by esterifying natural cellulose and acetic acid. This material has some advantages, including being nontoxic and reproducible and having good ­film-​­forming ability (­Zhang et al., 2021). Gumel and Dambatta (­2013) compared aqueous solutions of polyvinyl alcohol (­PVA), nitrocellulose, and a PVA/­nitrocellulose mixture as finishes on dyed goat leather. They found that the

282

Cellulose

Cellulose

Hide Tanning

Comparable physical and organoleptic properties to chrome-tanned leather tanning agent

• • • Leather

Cellulose

Improved strength and physical properties

Cellulose

Fullness without affecting the aesthetic property

Retanning • • • Leather Finishing

­FIGURE 19.1 

Function of cellulose in leather processing.

nitrocellulose coatings exhibit superior coating properties in almost every aspect. Products for processing leather containing nitrocellulose are currently found on the market (­Tanquimica, 2022; Nitroquímica, 2021). ­Figure  19.1 shows a diagram with the function of cellulose in each step of leather processing based on the examples cited in the literature.

COMPOSITES OF CELLULOSE AND SOLID LEATHER WASTE Leather wastes can be turned into valuable materials with the addition of cellulose. These wastes are used to develop composites for use in many areas. Zainescu et al. (­2014) used tanned and finished leather wastes to obtain polymeric compositions. The production process involved defibering chrome leather waste and mixing it with cellulose. During defibering, 6% of hydrochloric acid and boric acid were used and neutralized with 8% of sodium carbonate solution and 1% glycerol and a blend of natural rubber latex and synthetic latex based on acrylonitrile butadiene with tannin, soda ash, fish oil, and ­anti-​­foaming agent added. Then, the latex was precipitated with aluminum sulfate. The product obtained can be used in automotive, footwear, handbag, and bookbinding applications. Waste leather buff (­W LB) with cellulose was utilized to make biocomposites for packaging applications. Cellulose was dissolved in the ionic liquid ­1-­​­­allyl-­​­­3-​­methylimidazolium chloride and added 5%–​­25% of WLB. The cellulose and ­cellulose–​­WLB composite films were prepared by regenerating the cast solutions in a water coagulation bath followed by washing and drying. The composite films showed a higher percentage of elongation at break and thermal stability when compared to the matrix. The thermal stability produced was attributed to c­ ross-​­linked collagen protein leather fibers in WLB. The composite films showed good interfacial bonding between the cellulose and the leather fibers of WLB. The product may be considered for use in packaging and wrapping applications, such as wrappers (­Xia et al., 2015). Sartore et al. (­2016) developed a blend based on PH and poly(­­ethylene-­​­­co-​­vinyl acetate) (­EVA). PH is a ­chromium-​­free product of chemical hydrolysis from the waste of leather manufacturing. ­PH–​­EVA blends were prepared with different percentages and the EVA has different vinyl acetate contents. The addition of PH promotes a regular stiffening effect for all the materials, with the elongation at break over 900% for a PH of 35% and at approximately 600% for the biggest PH. The product obtained mostly from renewable sources represents a biodegradable material that appears

283

Beamhouse

Application of Cellulose in Leather

Rawhide trimmings

+ cellulose

Packaging

Tanning

Shoe insole Chrome shaving

Finishing

Sheets

Buffing dust

Agricultural

­FIGURE 19.2  Composites made from leather solid wastes and cellulose.

promising for several applications, such as in packaging or in agriculture as transplanting or mulching films with the additional fertilizing action of PH. Ashokkumar et al. (­2011) prepared flexible composite sheets made up of ­chromium-​­containing collagenous wastes (­CS) and derivatives of cellulose. The leather wastes were partially hydrolyzed and converted into composite sheets under microwaves with the addition of 2.­5 –​­20 wt% ­2-​ ­hydroxyethyl cellulose (­H EC). With 20% of HEC in the composite sheets, a strength of 3.14 MPa was achieved. The reduction in pores exhibits a better interfacial adhesion of HEC in CS. In addition, the thermal stability was higher in the sheets with more HEC. The developed ­CS–​­HEC composite sheets are suitable for leather product applications, due to their flexibility and thermomechanical properties. The composites made from leather solid wastes and cellulose are shown in ­Figure 19.2.

CONCLUSION Hide is a byproduct of the slaughterhouse that is turned into leather, a valuable commercial product. As this chapter demonstrates, cellulose is generally applied in the following stages of leather processing: tanning, retanning, and finishing. Cellulose is a renewable raw material that can replace many chemicals in the leather industry. Although solid leather wastes are generated during the processing of leather, they are turned into a valuable raw material that combined with cellulose produces composites for several applications, ranging from agricultural to packaging. In this way, cellulose can be one solution used to minimize the environmental issues of the leather industry.

284

Cellulose

REFERENCES Agustini, C., & Gutterres, M. (­2017). Biogas Production from Solid Tannery Wastes.In Vico. A. & Artemio, N. (­eds) Biogas: Production, Applications and Global Developments (­­pp. ­1–​­340). Nova Science Publishers, New York. Ashokkumar, M., Thanikaivelan, P., Krishnaraj, K., & Chandrasekaran, B. (­2011). Transforming chromium-​ ­containing collagen wastes into flexible composite sheets using cellulose derivatives: Structural, thermal, and mechanical investigations. Polymer Composites, 32(­6), 1010–​­1017. Brigham, C. (­2018). Biopolymers: Biodegradable Alternatives to Traditional Plastics. In Török, B. & Dransfield, T (­eds) Green Chemistry An Inclusive Approach (­­pp. ­753–​­770). Elsevier, Amsterdam. Ding, W., Yi, Y., Wang, Y. N., Zhou, J., & Shi, B. (­2019). Peroxide-​­periodate co-​­modification of carboxymethylcellulose to prepare polysaccharide-​­based tanning agent with high solid content. Carbohydrate Polymers, 224, 115169. Grand View Research. (­2020). Leather Goods Market Size, Share  & Trends Analysis Report. Grand View Research. https://­www.grandviewresearch.com/­industry-​­analysis/­leather-​­goods-​­market. Gumel, S.M., & Dambatta, B. (­2013). Application and evaluation of the performance of poly (­vinyl alcohol) and its blend with nitrocelulose in leather top coating. International Journal of Chemical Engineering and Applications, 4(­4), 249. Gutterres, M.,  & Mella, B. (­2015). Chromium in Tannery Wastewater. In Sharma, S. (­ed) Heavy Metals in Water: Presence, Removal and Safety (­­pp. ­315–​­344). Royal Society of Chemistry, Cambridge. Hansen, É., de Aquim, P.M., Hansen, A.W., Cardoso, J.K., Ziulkoski, A.L., & Gutterres, M. (­2020). Impact of post-​­tanning chemicals on the pollution load of tannery wastewater. Journal of Environmental Management, 269, 110787. Jiang, Z., Ding, W., Xu, S., Remón, J., Shi, B., Hu, C., & Clark, J.H. (­2020). A ‘­Trojan horse strategy’for the development of a renewable leather tanning agent produced via an AlCl 3-​­catalyzed cellulose depolymerization. Green Chemistry, 22(­2), 316–​­321. Jiang, Z., Xu, S., Ding, W., Gao, M., Fan, J., Hu, C., & Clark, J. H. (­2021). Advanced masking agent for leather tanning from stepwise degradation and oxidation of cellulose. Green Chemistry, 23(­11), 4044–​­4050. Kopp, V.V., Agustini, C.B., Gutterres, M., & Dos Santos, J.H.Z. (­2021). Nanomaterials to help eco-​­friendly leather processing. Environmental Science and Pollution Research, 28(­40), 55905–​­55914. Li, K., Yu, R., Zhu, R., Liang, R., Liu, G.,  & Peng, B. (­2019). pH-​­sensitive and chromium-​­loaded mineralized nanoparticles as a tanning agent for cleaner leather production. ACS Sustainable Chemistry  & Engineering, 7(­9), 8660–​­8669. Lv, S., Zhou, Q., Li, Y., He, Y., Zhao, H., & Sun, S. (­2016). Tanning performance and environmental effects of nanosized graphene oxide tanning agent. Clean Technologies and Environmental Policy, 18(­6), 1997–​­2006. Maina, P., Ollengo, M.A., & Nthiga, E.W. (­2019). Trends in leather processing: A review. International Journal of Scientific Research, 7(­8), 212–​­223. Nitroquímica. (­2021). Nitrocelulose para acabamento em couro. Nitroquímica. https://­nitro.com.br/­mercados/­ couro Sartore, L., Bignotti, F., Pandini, S., D’Amore, A., & Landro, L. (­2016). Green composites and blends from leather industry waste. Polymer Composites, 37(­12), 3416–​­3422. Selvaraju, S., Ramalingam, S., & Rao, J.R. (­2019). Polyanionic bio-​­emulsifier: A heteropolysaccharide based bio-​­composite for leather post tanning process. Journal of the American Leather Chemists Association, 114(­3), 72–​­79. Shi, J., Wang, C., Hu, Xiao, Y., & Lin, W. (­2019). Novel wet-​­white tanning approach based on laponite clay nanoparticles for reduced formaldehyde release and improved physical performances. ACS Sustainable Chemistry & Engineering, 7(­1), 1195–​­1201. Steffanello Piccin, J.S., & Guterres, M. (­2019). Otimização de parâmetros de transferência de massa e capacidade de adsorção de corante por resíduos de couro. Revista ­CIATEC-​­UPF, 11(­3), ­50–​­61. Tamilselvi, A., Jayakumar, G.C., Charan, K.S., Sahu, B., Deepa, P.R., Kanth, S.V. & Kanagaraj, J., (­2019). Extraction of cellulose from renewable resources and its application in leather finishing. Journal of Cleaner Production, 230, 694–​­699. Tanquimica. (­2022). Acabamento. http://­www.tanquimica.com.br/­categoria/­112,acabamento. Winter, C. (­ 2014). Caracterização de filmes poliméricos utilizados em acabamento de couros. Master Dissertation. Universidade Federal do Rio Grande do Sul,Porto Alegre, Brazil. Winter, C., Agustini, C. B., RS, M. E., & Gutterres, M. (­2018). Behavior of polymer films and its blends for leather finishing. Trends in Textile Engineering & Fashion Technology, 1(­4), 93–​­102.

Application of Cellulose in Leather

285

Winter, C., Schultz, M.E.R., & Gutterres, M. (­2015). Evaluation of polymer resins and films formed by leather finishing. Latin American Applied Research, 45, 213–​­217. Xia, G., Sadanand, V., Ashok, B., Obi Reddy, K., Zhang, J.,  & Rajulu, A. (­2015). Preparation and properties of cellulose/­ waste leather buff biocomposites. International Journal of Polymer Analysis and Characterization, 20(­8), 693–​­703. Yi, Y., Jiang, Z., Yang, S., Ding, W., Wang, Y.N., & Shi, B. (­2020). Formaldehyde formation during the preparation of dialdehyde carboxymethyl cellulose tanning agent. Carbohydrate Polymers, 239, 116217. Zainescu, G., Albu, L., Deselnicu, D., Constatinescu, R., Vasilescu, A., Nichita, P., & Sirbu, C. (­2014). A new concept of complex valorization of leather wastes. Materiale Plastice, 51(­1), ­90–​­93. Zhang, J., Bao, Y., Guo, M., & Peng, Z. (­2021). Preparation and properties of nano SiO2 modified cellulose acetate aqueous polymer emulsion for leather finishing. Cellulose, 28(­11), 7213–​­7225.

20

Utilization of Cellulose in Wastewater Treatment Nur Syazwani Abd Rahman and Norhafizah Saari Universiti Sains Malaysia

CONTENTS Introduction..................................................................................................................................... 287 Forms of Cellulose.......................................................................................................................... 288 Modification of Cellulose...............................................................................................................290 Overview.................................................................................................................................... 290 Types of Cellulose Modification................................................................................................ 290 Dissolution of Cellulose........................................................................................................ 290 Allomorphic Modification..................................................................................................... 291 Derivation of Cellulose.......................................................................................................... 291 Modified Cellulose for Effluent Treatment..................................................................................... 294 The Challenge and Concern of Using Cellulose in Wastewater Treatment.................................... 294 References....................................................................................................................................... 296

INTRODUCTION Water pollution issues have become a serious concern nowadays. Due to improper handling and management, the water quality has deteriorated tremendously, which has had a big impact, especially on the living organisms (­Sjahro et al., 2021). So, what are the consequences of this phenomenon? According to the 2018 edition of the United Nations (­UN) World Water Development Report (­W WDR), researchers have predicted that by 2050, water scarcity will affect about 57% of the global population for at least 1 month per year in some areas (­Boretti & Rosa, 2019; World Water Assessment Programme (­United Nations), 2018). In order to address the issues of water demand and quality, researchers are now eager to find a new alternative in the development of sustainable treatment technologies (­Jamshaid et al., 2017). In the process of treating wastewater, the fundamental physical, chemical, and biological basis of the contaminant should be considered. Wastewater comes from either a point source (­singular or identified source) or a ­non-​­point source (­combination of pollutants in larger areas). Commonly, water contaminants include organic and inorganic pollutants, synthetic organic chemicals, heavy metals, and nutrients (­Jamshaid et al., 2017). Thus, a proper and specific approach is required depending on the properties and characteristics of the effluent removed (­Sjahro et al., 2021). Various methods have been used in solving the issues of water pollution, such as reverse osmosis, chemical precipitation, coagulation/­flocculation, ion exchange, and electrochemical technologies (­­Zamora-​­Ledezma et al., 2021). However, most of these conventional methods require a large number of chemicals, a high operational cost, poor regeneration, and high electric power consumption. Due to this reason, researchers have recently developed a treatment method called adsorption technology. The efficiency of using this method to remove organic pollutants was reported at about 99.9% (­­Zamora-​ ­Ledezma et al., 2021; Ali et al., 2012). The selection of materials also plays an important role in this application. A few aspects need to be considered, including the availability, cost, and performance of the material. Materials with DOI: 10.1201/9781003358084-20

287

288

Cellulose

a high specific area, low toxicity, good mechanical strength, and thermal stability would be among the best selections since they will help in increasing the adsorption capacity and efficiency of the effluent removal and, at the same time, do not chemically react with the effluent and produce a new substance that might worsen the treated water condition. Since biomass and biomaterials have become an alternative and have good potential in wastewater treatment, their demand and extended focus have been studied among researchers. This chapter presents a review of cellulose as the main material for wastewater treatment. It includes the form of cellulose commonly used, modification of cellulose, effluent removal using modified cellulose, and common challenges that occur during the application.

FORMS OF CELLULOSE The physical form of adsorbent material is an important aspect in removing various pollutants that have contaminated fresh water sources. For adsorbents that use natural fibers as their main raw material, the most common physical forms of cellulose absorbent material that have been widely used include powder or granules, fine particles, fiber, hydrogel, film, or membranes (­Liu et al., 2002). The powder form of cellulose is commonly used in the production of adsorbents such as activated carbon. Generally, the process to produce activated carbon adsorbent is divided into two steps: carbonization and physical (­carbon dioxide or water steam) or chemical (­acid or base) activation (­Rodríguez Correa et al., 2017). The decomposition and formation of char during the process releases oxygen and hydrogen compounds. Furthermore, the condensable volatile compound is formed by cleaving weak bonds such as the ­C–​­O bond and ­the -­​­­O-​­4 structure (­Rodríguez Correa et al., 2017; Shen et al., 2017). This reaction results in the formation of ­single-​­and ­multi-​­phenolic compounds (­Faravelli et al., 2010; Rodríguez Correa et al., 2017). Dorrestijn et al. (­2000) asserted that during the secondary phase of the reaction, the solid structure begins to rearrange due to the crosslinking of C ­ –​­C bonds, resulting in the formation of char. Moreover, at temperatures greater than 500°C, the aromatic structure is observed to grow and also rearrange into a turbostratic graphene sheet (­Kercher & Nagle, 2003). The advantage of using cellulose in the fiber form is that all the impurities can be removed during the pretreatment process, which also helps in exposing the OH functional group of the cellulose. Then, the hydroxyl groups of the cellulose are modified to improve sorption and selectivity (­Wang et al., 2016). As shown in ­Figure 20.1, pretreatment helps in increasing the roughness of the surface of the fiber and exposes more cavities, thus increasing the rate of modification whereby more OH reactive groups are exposed during the process. In the case of cellulose in the fiber form, the fiber typically goes through a fabrication process before being treated to produce a h­ igh-​­sorption and h­ igh-​­selectivity water adsorbent by modifying the hydroxyl groups of the cellulose (­Wang et al., 2016). Cellulose in the fiber form is used to produce

­FIGURE 20.1  The effect of (­a) before and (­b), (­c) after treatment process. Reproduced with permission from Adel Salih et al. (­2020). Copyright, CC BY License.

Utilization of Cellulose in Wastewater Treatment

289

cellulose acetate/­zeolite (­CA/­Z) composite fibers using the technique of wet spinning. Zeolite particles embedded in the cellulose acetate act as a polymer matrix. The porous structure of the fiber, with pore sizes ranging from 300 to 500 nm, allows heavy metal ions such as Cu (­II) and Ni (­II) to pass through and diffuse quickly into internal pores. The zeolite particles then act as adsorptive sites with a size of about 1 μm. The maximum adsorption is found to be between 28.57 and 16.95 mg/­g. According to Alila and Boufi (­2009), aromatic organic compounds such as 2­ -​­naphtol, nitrobenzene, chlorobenzene, dichlorobenzene, trichlorobenzene, and chlorophenol can be removed by modifying cellulose fibers in a heterogeneous environment by grafting long hydrocarbon chains. The reagents responsible for grafting the various hydrocarbons in this study are ­4-​­4’-​­methylenebis (­phenyl isocyanate) (­MDI) and N, N’-​­carbodiimidazole. During the adsorption process, the organic pollutants will ­self-​­assemble at the polar active sites on the modified fiber surface. The findings showed that the adsorption capacity had improved after the chemical modification of the fibers’ surface, increased from 400 to 1,000 mol/­g for the modified substrates compared with virgin fibers, which increased from 20 to 50 mol/­g. The membrane form is one of the physical forms of cellulose adsorbent materials, which are mostly used to remove trapped particles and contaminants, especially oil, from wastewater. The filtration process by membrane is normally carried out in a s­ emi-​­batch process through continuous withdrawal of permeates and recycling of ­oil-​­enriched ­non-​­permeates (­Madaeni et al., 2013). The benefits of using this membrane technology include less pollution and lower energy consumption, which reduces total processing costs when compared to other conventional methods. In addition, absorbents in the membrane form in processes such as microfiltration, nanofiltration, ultrafiltration, and reverse osmosis were found to be highly effective in removing contaminants in wastewater treatment (­Gebru & Das, 2017a, 2017b, 2018). In a study by Juang and Shiau (­2000), the membrane synthesis involved the utilization of a commercial membrane solution of cellulose triacetate and cellulose nitrate. In another study, chitosan membranes were used with the aim of removing metal ions such as Cu (­II) and Zn (­II) from synthetic wastewater (­Chen et al., 2009). Ultrafiltration membranes with high permeability and excellent antifouling properties for oil/­water emulsion separation were created using cellulose acetate and polyacrylonitrile (­PAN). Researchers have recently discussed four membrane preparation methods for wastewater filtration: direct use of biosynthesized bacterial cellulose (­BC) membranes, electrospun mats impregnated with cellulose nanomaterial, vacuum filtration, and composite membranes (­Dufresne, 2017). BC membranes were synthesized by bacteria and were formed after 2 days of incubation. Wanichapichart and team produced BC membranes using Acetobacter xylinum as a ­cellulose-​­producing bacterium in a culture medium. The produced cellulose membrane sheet was tested for filtration of bovine serum albumin and Chlorella sp. The low porosity of this membranes was reported to be around 1.4%– ​­2.4% with an average pore size of 0.08 μm (­Wanichapichart et al., 2003). The hydraulic permeability coefficient of the BC membrane depended on cell density and time during the forming process. An aqueous oxidation system based on TEMPO/­NaBr/­NaClO impregnated into an electrospun PAN nanofibrous scaffold supported by a poly(­ethylene terephthalate) (­PET) nonwoven substrate used for cellulose nanocrystals (­CNCs) preparation was used to prepare electrospun mats (­Ma et al., 2012). It had the capability of full retention against bacteria such as E. coli and B. diminuta. Vacuum filtration is an accessible method to produce the layered structure of nanocellulose membranes. CNC membranes prepared from tunicin CNC via ­vacuum-​­assisted filtration onto nylon filter membranes were found to be highly efficient in the separation of oily water, which includes ­oil-­​­­in-​­water and ­water-­​­­in-​­oil emulsions (­Cheng et al., 2017). Composite membranes that consist of ­TEMPO-​­oxidized cellulose nanofiber (­CNF) and cellulose triacetate can be prepared by casting ­1-­​­­methyl-­​­­2-​­pyrrolidinone (­NMP) mixtures (­Kong et al., 2014). This technique improved the permeation flux and a­ nti-​­fouling performance due to the hydrophilicity of the surface, which had been imparted by ­TEMPO-​­oxidized CNF. Hydrogel is the most advanced form of adsorbent type that is mainly made from p­ olysaccharide-​ ­based material and involves ­crosslinking-­​­­polysaccharide-​­based materials with other functional groups or coupling agents in order to produce a ­water-​­insoluble crosslinked network, where the nanocellulose acts as an additive, binder, or reinforcing agent (­Carpenter et al., 2015).

290

Cellulose

MODIFICATION OF CELLULOSE Overview Over the years, cellulose has been widely studied and applied in water treatment. The unique and attractive characteristics have given it a promising potential to be applied as a membrane and adsorbent due to its excellent mechanical, physical, and chemical properties (­Jamshaid et  al., 2017). Moreover, cellulose is also more stable, nontoxic, and ­eco-​­friendly, which makes it a good option for raw material selection in wastewater treatment (­Yang et al., 2020). Availability of cellulose materials is also abundant since they can be obtained from many sources such as wood and ­non-​­wood plants, bacteria such as algae, and ­cellulose-​­containing animals such as tunicates (­Seddiqi et al., 2021), among which, wood and ­non-​­wood have become the most preferred sources since they are easily obtained. According to Felgueiras et al. (­2021), cotton is the most often used natural fabric for apparel, home furnishings, and industrial products, accounting for almost 90% of all natural fibers. ­Table 20.1 shows the different types of natural fibers and their cellulose composition as a percentage. Cellulose is commonly found in the fiber wall along with other lignocellulosic compounds. It is a linear polymer with a­ -​­1,4 linkage and a ­glucose-​­repeating unit joint. Despite the abundance of hydroxyl groups, the string intermolecular hydrogen bonding and compact structure of cellulose make it difficult to penetrate and replace or dissolve in water (­Phanthong et al., 2018; Felgueiras et al., 2021). Therefore, cellulose modification was required to meet the desired industrial requirements. The modification may involve a physical or chemical approach.

Types of Cellulose Modification Cellulose modification can be carried out through several methods, such as dissolution, allomorphic modifications (­chemical reagents, mercerization, and thermal treatment), and derivatization via chemical modification (­Park et al., 2010; Sjahro et al., 2021). Each type of modification may have a different effect on the final product. Dissolution of Cellulose The linear structure of cellulose, combined with strong intermolecular hydrogen bonding, has made it difficult to penetrate or replace, which makes cellulose insoluble in water despite the abundance of

­ ABLE 20.1 T Types of Natural Fiber and its Cellulose Percentage Composition (­Hernandez & Rosa, 2016) Types of Fiber Banana Coir Cork bark Corn cob Cotton Flax Hemp Jute Sisal Wheat stalk

Origin

Percentage Cellulose (%)

Leaf Fruit Leaf Stalk Seed Stem Stem Bast Leaf Stalk

60.­0–​­65.0 32.­0–​­43.0 12.­0–​­25.0 33.­7–​­41.2 82.­7–​­95.0 64.­0–​­84.0 67.­0–​­78.0 51.­0–​­78.0 60.­0–​­73.0 30.­0–​­35.0

291

Utilization of Cellulose in Wastewater Treatment

hydroxyl groups. Thus, dissolution of cellulose is one approach that can be considered, which commonly involves the utilization of organic solvents. However, only selected organic solvents can be used to dissolve cellulose without prior chemical modification, such as ionic liquids, amine oxides, aqueous alkali solutions, inorganic salts, organic solvents, and inorganic molten salt hydrates (­Chen et al., 2009). According to Acharya et  al. (­2021), theoretically, in order for dissolution of cellulose to take place, the native ­hydrogen-​­bonded network, especially in the crystalline region, should be broken. However, by using n­ on-​­derivatizing solvent systems, the hydrogen bonding between cellulose is disrupted by establishing new hydrogen bonds with the hydroxyl group of the cellulose, which at the same time destroys the crystalline structure. Regenerated cellulose, such as rayon, is commonly produced by dissolving cellulose in a specific solvent and regenerating it via precipitation (­Sjahro et al., 2021). Viscous rayon can be used in treating ­water-​­soluble zinc (­Mamyachenkov et al., 2017). Allomorphic Modification In allomorphic modification, the process involves the conversion of cellulose I to cellulose II, III, and IV. Among all forms of cellulose, cellulose I is most commonly found in its native form, which is converted into cellulose II using alkaline treatment. Cellulose III is produced via chemical treatment of cellulose I or II using certain amines or liquid ammonia. However, cellulose IV cannot be produced directly from cellulose I. Cellulose IV can be obtained by treating cellulose II and III at high temperatures using glycerol or by directly converting cellulose III to IV via thermal treatment (­Park et al., 2010; Sjahro et al., 2021). Derivation of Cellulose The derivation of cellulose, also known as cellulose modification, involves many types of modifications, such as polymer grafting, esterification, etherification, hydrolysis, and others. Different types of modifications may have a different effect on the properties of the cellulose. Depending on the preference, it entails changing or substituting a new functional group at the hydroxyl cellulose. ­Table 20.2 summarizes the types of modifications. ­ ABLE 20.2 T Types of Fiber Modification Types of Modification

Attached/­Alter Group

Perform Using

Esterification

­O-​­C=O

Oxidation

Oxidant media

Alkaline

Use as an activating agent NaOH in production of activated carbon Substitute silyl group Common silane type • ­gamma-​­aminopropyl triethoxy silane (­APS) • ­gamma-​­diethylenetriaminopropyl trimethoxy silane (­TAS) • ­gamma-​­ methacryloxypropyl trimethoxy silane (­MPS) Combination two or more • RAFT polymers • NMF • ATRP

Silylation

Grafting

Carboxylic acid, alkyd, alkyl ketene dimer, acid chloride • Superoxide anion (­O2–) • Hydrogen peroxide (­H2O2)

Effect of Modification Increase hydrophobicity of cellulose surface Act as an excellent ­coagulation–​­flocculation agent. Increase micropores and diameter of cavities Normally used to capture CO2 from air

Grafted cellulose absorbs better than common sorbate.

292

Cellulose

F­ IGURE 20.2  (­a) The location of the OH functional group on the surface of the fiber. (­b) and (­c) The effect of esterification on the molecular structure of the cellulose. Reproduced with permission from Wang et al. (­2018). Copyright, CC BY License.

As shown in F ­ igure  20.2, the mechanism of the process for esterification involves acylation of cellulose using carboxylic acid under acidic conditions or anhydride reaction in base or Lewis acid concentration. The OH groups of cellulose (­­Figure 20.2a), especially at C2, C3, and C6, are substituted by the ester group (­­Figure 20.2b and c). This type of modification helps increase the hydrophobicity of cellulose. Meanwhile, modification by oxidation of cellulose involves oxidation media such as sodium periodate or hydrogen periodate, nitroxyl radicals, strong acids, or ozone (­Sang et al., 2017). Among these, the periodate media (­sodium periodate or hydrogen periodate) and nitroxyl radicals such as TEMPO (­2,2,6,­6 -­​­­tetramethylpiperidine-­​­­1-​­oxyl) are the most preferred media used since they can selectively oxidize the OH groups in cellulose. The difference between the periodate and nitroxyl media is that the periodate can cleave the carbon bond between C2 and C3 of the cellulose and oxidize the C2 and C3 of the hydroxyl groups. On the other hand, the nitroxyl radicals can only oxidize the primary OH groups, as shown in ­Figure 20.3. Alkaline modification has been considered one of the simplest methods to improve the interfacial bonding between the fibers (­Williams et al., 2011). During the modification process, the hydroxide ions from NaOH will destroy the hydrogen bonding between the cellulose molecules (­­Figure 20.4). Thus, it helps to increase the active OH groups on the surface of the fiber and, at the same time, removes the cementing materials such as wax and impurities. As a result, the surface area of the fiber wall increases, as do the number of micropores and the diameter of the cavities. Modification via silylation involves the utilization of silane coupling agents such as g­ amma-​ ­diethylenetriaminopropyl trimethoxy silane (­TAS), ­gamma-​­methacryloxypropyl trimethoxy silane (­MPS), and many more. The OH groups of cellulose are substituted by the silanol group

Utilization of Cellulose in Wastewater Treatment

293

F­ IGURE 20.3  Effect of cellulose oxidation using nitroxyl radicals (­­TEMPO-​­mediated oxidation) and periodate oxidation.

­FIGURE  20.4  The alkaline modification of cellulose. Reproduced with permission from Williams et  al. (­2011). Copyright, CC BY License.

F­ IGURE  20.5  The silylation process of cellulose. Reproduced with permission from Coelho Braga de Carvalho et al. (­2021). Copyright, CC BY License.

on the surface of the cellulose and thus increase the hydrophobicity of the surface (­­Figure 20.5) (­Jankauskaitė et al., 2020). Cellulose grafting is defined as combining two or more polymers with the backbone of the cellulose chain. A few techniques can be used in the grafting process, such as reversible addition fragmentation transfer (­RAFT), radical polymerization, ­ring-​­opening polymerization, and many more. Commonly, most of the modification takes place at the hydroxyl group of C2, C3, and C6 of the anhydroglucose unit since it is easily accessible. The effect of grafting may alter the physical and chemical properties of the fiber.

294

Cellulose

MODIFIED CELLULOSE FOR EFFLUENT TREATMENT Water contaminants are generally generated from the agricultural sector, domestic activities, and industrial activities, which have been constantly increased to fulfill the demands of food production and the sustenance of the human population globally (­Hokkanen et al., 2016b; Gupta et al., 2015). The contaminants that have been detected polluting the fresh water include heavy metal ions, dyes, oil spills, microbes, organic and inorganic micropollutants, metalloids, nutrients, and synthetic organic chemicals (­Abouzeid et al., 2019; Hokkanen et al., 2016a; Jamshaid et al., 2017). Toxic heavy metals, for example, have a high potential for causing cancer and other risks to human health by bioaccumulating in the human body through water consumption. Besides, biological pollutants have been found to exist in large quantities in our water resources, such as worms, algae, bacterial species, and viruses, which results from the degradation of organic matter, animal waste, and human activity (­Abouzeid et al., 2019). Oil spills are one of the main pollutants in fresh water that normally occur in offshore oil exploration or during transportation of the oil sources (­Munirasu et  al., 2016). Oil spill accidents have become a major concern because it is estimated that 30% of the world’s oil is spilled (­Fakhru’­l-​­Razi et al., 2009). In addition to oil spills, organic matter, also known as total organic carbon (­TOC), is one of the pollutants that contaminate fresh water. These hydrocarbons include benzene, toluene, ethylbenzene, and xylenes (­BTEX), naphthalene, phenanthrene, dibenzothiophene (­N PD), polyaromatic hydrocarbons (­PAHs), phenols, carboxylic acids, and low molecular weight aromatic compounds. The low solubility of this hydrocarbon has caused the presence of small oil droplets in water (­Peng et al., 2020). Furthermore, another pollutant in produced or processed water is inorganic matter, which includes cations (­Na, K, Ca, Mg, Ba, Sr, Fe), anions (­Cl, SO, CO, HO), and heavy metals (­cadmium, chromium, copper, lead, mercury, nickel, silver, and zinc). Moreover, radioactive materials (­­radium-​­226 and r­adium-​­228) can also be detected in produced or processed water (­Igunnu & Chen, 2014). Suspended solid matters such as solids, sand, clay, corrosion, wax, bacteria, and asphaltenes have been found in processed water (­Munirasu et al., 2016). Modification of cellulose biomaterials with respect to wastewater treatment is being widely studied due to their excellent physical, chemical and mechanical properties. Modified cellulose such as cellulose gels, cellulose composites, cellulose derivatives, functionalized cellulose and nanocrystalline cellulose has been found to be effective in removing pollutants present in wastewater. As discussed under a previous subtopic, cellulose can be chemically modified through many methods such as esterifications, halogenations, oxidation, etherification, grafting, and others. Furthermore, it also can be modified by combining with other materials to form composites beads. ­Table 20.3 presents an overview of cellulose modification with respect to the removal of wastewater pollutants via adsorption process. Generally, as illustrated in ­Figure 20.5, adsorption occurs when the adsorbate molecules diffuse to the surface of the adsorbent and are migrated into the pores of the adsorbent. Finally, the molecules will be adsorbed on the surface of the adsorbent by monolayer or multilayer adsorption (­Bharathi & Ramesh, 2013) (­­Figure 20.6).

THE CHALLENGE AND CONCERN OF USING CELLULOSE IN WASTEWATER TREATMENT Wastewater treatment is among the main concerns in water management. It should be taken seriously since the uncontrollable discharge of wastewater will have serious effects on the health and water balance of the ecosystem (­Nguyen et al., 2021). As a result, researchers have found cellulose as a potential raw material for wastewater treatment. In the utilization of nanocellulose, the biggest drawback is limited permeance. Most of the nanopapers produced, as reported by researchers, has narrow pore sizes and thick active layers,

295

Utilization of Cellulose in Wastewater Treatment

F­ IGURE 20.6  The f­ our-​­stage mechanism of adsorption as proposed by Sivakumar and Palanisamy (­2010). Reproduced with permission from Bharathi and Ramesh (­2013). Copyright, CC BY License.

­ ABLE 20.3 T Cellulose Modification with Respect to Pollutants Removed From Wastewater Cellulose Modification Organic/­inorganic treatment

Acid treatment Cellulose gel

Contaminants Removed

The Process Involved Mercerized cellulose with NaOH, followed by washing with distilled water and acetone. Then reacted with succinic anhydride under pyridine reflux Using carbonated hydroxyapatite (­CHA) to produce ­CHA-​­modified microfibrillated cellulose Modified with thionyl chloride followed by ethylene sulfide Modified with maleic anhydride Cellulose is etherified, oxidized, and then modified to a Schiff base using lysine Using iron oxyhydroxide to form cellulose beads Carboxymethyl cellulose crosslinked with epichlorohydrin (­ECH) Using cellulose graft polyacrylamide and hydroxyapatite

Cu , Cd 2+

2+

and Pb

2+

References Gurgel et al. (­2008)

Cd 2+, Ni 2+

Hokkanen et al. (­2014)

Pb, Zn, Co, Ni, Cu and Cd Hg (­III) Mercury ions

Silva Filho et al. (­2013)

Arsenate and arsenite PBb (­II), Ni (­II) and Cu (­II) Cu (­II)

Zhou et al. (­2012) Kumari and Chauhan (­2014) Guo et al. (­2013) Yang et al. (­2011) Zwain et al. (­2014) (Continued )

296

Cellulose

­TABLE 20.3 (Continued) Cellulose Modification with Respect to Pollutants Removed From Wastewater Cellulose Modification Cellulose composites

The Process Involved

Using sodium montmorillonite (­NaMMT) Combined with chitosan (­CTS) Using ionic liquids to form cellulose and chitin composites Combined TiO2 with cellulose to form nanocomposites Cellulose derivatives Synthesizing graft copolymers from cellulose biopolymers Nanoparticles of zirconium dioxide were grown on a cellulose matrix Functionalized Cellulose acetate combined with cellulose tetraethoxysilane Functionalized a hybrid material of cellulose using glycidylmethacrylate and tetraethylenepentamine Nanocellulose Cellulose nanocrystals were chemically modified using succinic anhydride and sodium bicarbonate Using xanthated nano banana cellulose

Contaminants Removed

References

Cr (­VI) Heavy metals Cu (­II), Zn (­II), Cr (­VI), Ni (­II) and Pb (­II) Pb

Kumar et al. (­2012) Wu et al. (­2010) Sun et al. (­2009)

Pb 2+, Zn 2+,Cu 2+,Cd 2+

Singha and Guleria (­2014)

Co 2+, Cd 2+, Cr 3+, Fe 3+, Cu 2+, Zn 2+, Ni 2+, Zr 4+ Cr (­VI)

Khan et al. (­2013)

Ag (­I), Cu (­II), Hg (­II)

Donia et al. (­2012)

Pb 2+, Cd 2+

Yu et al. (­2013)

Cd (­II)

Pillai et al. (­2013)

Li et al. (­2015)

Khan et al. (­2013)

especially in the ultrafiltration range, which may lead to low permeance and limit the efficiency of the filter (­Nguyen et al., 2021). Another concern that should be considered is the possibility of poor durability and leakage of the embedded effluent during the purification process (­Nguyen et al., 2021). Furthermore, the filter paper’s low mechanical strength may allow some fine fiber particles to enter the treated water. The exposure to the fine particles may also have a ­short-​­term effect since it is considered a carcinogenic material. As a result, more research is needed to overcome the challenges of contamination and ­post-​­treatment issues (­Wang et al., 2020).

REFERENCES Abouzeid, R. E., Khiari, R., El-​­Wakil, N., & Dufresne, A. (­2019). Current state and new trends in the use of cellulose nanomaterials for wastewater treatment. Biomacromolecules, 20(­2), 573–​­597. Acharya, S., Liyanage, S., Parajuli, P., Rumi, S. S., Shamshina, J. L., & Abidi, N. (­2021). Utilization of cellulose to its full potential: A review on cellulose dissolution, regeneration, and applications. Polymers, 13(­24), 4344. Adel Salih, A., Zulkifli, R., & Azhari, C. H. (­2020). Tensile properties and microstructure of single-​­cellulosic bamboo fiber strips after alkali treatment. Fibers, 8(­5), 26. Ali, I., Asim, M., & Khan, T. A. (­2012). Low cost adsorbents for the removal of organic pollutants from wastewater. Journal of Environmental Management, 113, 170–​­183. Alila, S., & Boufi, S. (­2009). Removal of organic pollutants from water by modified cellulose fibres. Industrial Crops and Products, 30(­1), 93–​­104. Bharathi, K. S., & Ramesh, S. T. (­2013). Removal of dyes using agricultural waste as low-​­cost adsorbents: A review. Applied Water Science, 3(­4), 773–​­790. Boretti, A., & Rosa, L. (­2019). Reassessing the projections of the world water development report. NPJ Clean Water, 2(­1), 15. Carpenter, A. W., de Lannoy, C. F., & Wiesner, M. R. (­2015). Cellulose nanomaterials in water treatment technologies. Environmental Science & Technology, 49(­9), 5277–​­5287.

Utilization of Cellulose in Wastewater Treatment

297

Chen, W., Su, Y., Zheng, L., Wang, L., & Jiang, Z. (­2009). The improved oil/­water separation performance of cellulose acetate-​­graft-​­polyacrylonitrile membranes. Journal of Membrane Science, 337(­1), 98–​­105. Cheng, Q., Ye, D., Chang, C., & Zhang, L. (­2017). Facile fabrication of superhydrophilic membranes consisted of fibrous tunicate cellulose nanocrystals for highly efficient oil/­water separation. Journal of Membrane Science, 525, 1–​­8. Coelho Braga de Carvalho, A. L., Ludovici, F., Goldmann, D., Silva, A. C., & Liimatainen, H. (­2021). Silylated thiol-​­containing cellulose nanofibers as a bio-​­based flocculation agent for ultrafine mineral particles of chalcopyrite and pyrite. Journal of Sustainable Metallurgy, 7(­4), 1506–​­1522. Donia, A. M., Atia, A. A., & Abouzayed, F. I. (­2012). Preparation and characterization of nano-​­magnetic cellulose with fast kinetic properties towards the adsorption of some metal ions. Chemical Engineering Journal, 191, 22–​­30. Dorrestijn, E., Laarhoven, L. J. J., Arends, I. W. C. E., & Mulder, P. (­2000). The occurrence and reactivity of phenoxyl linkages in lignin and low rank coal. Journal of Analytical and Applied Pyrolysis, 54(­1), 153–​­192. Dufresne, A. (­2017). Nanocellulose. From Nature to High Performance Tailored Materials (­2nd ed., ­p. 650). De Gruyter, Berlin, Boston. Fakhru’l-​­Razi, A., Pendashteh, A., Abdullah, L. C., Biak, D. R. A., Madaeni, S. S., & Abidin, Z. Z. (­2009). Review of technologies for oil and gas produced water treatment. Journal of Hazardous Materials, 170 (­2), 530–​­551. Faravelli, T., Frassoldati, A., Migliavacca, G., & Ranzi, E. (­2010). Detailed kinetic modeling of the thermal degradation of lignins. Biomass and Bioenergy, 34(­3), 290–​­301. Felgueiras, C., Azoia, N. G., Gonçalves, C., Gama, M., & Dourado, F. (­2021). Trends on the Cellulose-​­based textiles: Raw materials and technologies. Frontiers in Bioengineering and Biotechnology, 29, 608826. Gebru, K. A., & Das, C. (­2017a). Removal of bovine serum albumin from wastewater using fouling resistant ultrafiltration membranes based on the blends of cellulose acetate, and PVP-​­TiO2 nanoparticles. Journal of Environmental Management, 200, 283–​­294. Gebru, K. A., & Das, C. (­2017b). Removal of Pb (­II) and Cu (­II) ions from wastewater using composite electrospun cellulose acetate/­titanium oxide (­TiO2) adsorbent. Journal of Water Process Engineering, 16, 1–​­13. Gebru, K. A.,  & Das, C. (­2018). Removal of chromium (­VI) ions from aqueous solutions using amine-​ i­mpregnated TiO2 nanoparticles modified cellulose acetate membranes. Chemosphere, 191, 673–​­684. Guo, C., Zhou, L., & Lv, J. (­2013). Effects of expandable graphite and modified ammonium polyphosphate on the flame-​­retardant and mechanical properties of wood flour-​­polypropylene composites. Polymers and Polymer Composites, 21(­7), 449–​­456. Gupta, V. K., Nayak, A., & Agarwal, S. (­2015). Bioadsorbents for remediation of heavy metals: Current status and their future prospects. Environmental Engineering Research, 20(­1), 1–​­18. Gurgel, L. V. A., Júnior, O. K., Gil, R. P. de, F., & Gil, L. F. (­2008). Adsorption of Cu(­II), Cd(­II), and Pb(­II) from aqueous single metal solutions by cellulose and mercerized cellulose chemically modified with succinic anhydride. Bioresource Technology, 99(­8), 3077–​­3083. Hernandez, C.,  & Rosa, D. D. (­2016). Extraction of cellulose nanowhiskers: Natural fibers source, methodology and application. In A. Méndez-​­Vilas  & A. Solano-​­Martín (­Eds.), Polymer Science: Research Advances, Practical Applications and Educational Aspects (­­pp. 232–​­242). Formatex Research Center, Pennsylvania. Hokkanen, S., Bhatnagar, A., Repo, E., Lou, S., & Sillanpää, M. (­2016a). Calcium hydroxyapatite microfibrillated cellulose composite as a potential adsorbent for the removal of Cr(­VI) from aqueous solution. Chemical Engineering Journal, 283, ­445–​­452. Hokkanen, S., Bhatnagar, A., & Sillanpää, M. (­2016b). A review on modification methods to cellulose-​­based adsorbents to improve adsorption capacity. Water Research, 91, 156–​­173. Hokkanen, S., Repo, E., Westholm, L. J., Lou, S., Sainio, T.,  & Sillanpää, M. (­2014). Adsorption of Ni2+, Cd2+, PO43− and NO3− from aqueous solutions by nanostructured microfibrillated cellulose modified with carbonated hydroxyapatite. Chemical Engineering Journal, 252, 64–​­74. Igunnu, E. T., & Chen, G. Z. (­2014). Produced water treatment technologies. International Journal of ­Low-​ C ­ arbon Technologies, 9(­3), 157–​­177. Jamshaid, A., Hamid, A., Muhammad, N., Naseer, A., Ghauri, M., Iqbal, J., Rafiq, S., & Shah, N. S. (­2017). Cellulose-​­based materials for the removal of heavy metals from wastewater – ​­An overview. ChemBioEng Reviews, 4(­4), 240–​­256. Jankauskaitė, V., Balčiūnaitienė, A., Alexandrova, R., Buškuvienė, N., & Žukienė, K. (­2020). Effect of cellulose microfiber silylation procedures on the properties and antibacterial activity of polydimethylsiloxane. Coatings, 10 (­567), ­1–​­21.

298

Cellulose

Juang, R.-​­S., & Shiau, R.-​­C. (­2000). Metal removal from aqueous solutions using chitosan-​­enhanced membrane filtration. Journal of Membrane Science, 165(­2), 159–​­167. Kercher, A. K., & Nagle, D. C. (­2003). Microstructural evolution during charcoal carbonization by X-​­ray diffraction analysis. Carbon, 41(­1), 15–​­27. Khan, S. B., Alamry, K. A., Marwani, H. M., Asiri, A. M., & Rahman, M. M. (­2013). Synthesis and environmental applications of cellulose/­ZrO2 nanohybrid as a selective adsorbent for nickel ion. Composites Part B: Engineering, 50, 253–​­258. Kong, L., Zhang, D., Shao, Z., Han, B., Lv, Y., Gao, K., & Peng, X. (­2014). Superior effect of TEMPO-​­oxidized cellulose nanofibrils (­TOCNs) on the performance of cellulose triacetate (­CTA) ultrafiltration membrane. Desalination, 332(­1), 117–​­125. Kumar, A. S. K., Kalidhasan, S., Rajesh, V.,  & Rajesh, N. (­2012). Application of cellulose-​­clay composite biosorbent toward the effective adsorption and removal of chromium from industrial wastewater. Industrial & Engineering Chemistry Research, 51(­1), 58–​­69. Kumari, S., & Chauhan, G. S. (­2014). New cellulose–​­Lysine Schiff-​­base-​­based sensor–​­adsorbent for mercury ions. ACS Applied Materials & Interfaces, 6(­8), 5908–​­5917. Li, Y., Cao, L., Li, L., & Yang, C. (­2015). In situ growing directional spindle TiO2 nanocrystals on cellulose fibers for enhanced Pb2+ adsorption from water. Journal of Hazardous Materials, 289, 140–​­148. Liu, M., Deng, Y., Zhan, H., & Zhang, X. (­2002). Adsorption and desorption of copper(­II) from solutions on new spherical cellulose adsorbent. Journal of Applied Polymer Science, 84(­3), 478–​­485. Ma, H., Burger, C., Hsiao, B. S., & Chu, B. (­2012). Nanofibrous microfiltration membrane based on cellulose nanowhiskers. Biomacromolecules, 13(­1), 180–​­186. Madaeni, S. S., Gheshlaghi, A., & Rekabdar, F. (­2013). Membrane treatment of oily wastewater from refinery processes. ­Asia-​­Pacific Journal of Chemical Engineering, 8(­1), 45–​­53. Mamyachenkov, S. V., Anisimova, O. S., & Egorov, V. V. (­2017). Investigation of viscose rayon manufacturing sludges, considered as a raw material for zinc production. KnE Materials Science, 2, 182–​­187. Munirasu, S., Haija, M. A., & Banat, F. (­2016). Use of membrane technology for oil field and refinery produced water treatment—​­A review. Process Safety and Environmental Protection, 100, 183–​­202. Nguyen, P. X. T., Ho, K. H., Nguyen, C. T. X., Do, N. H. N., Pham, A. P. N., Do, T. C., Le, K. A., & Le, P. K. (­2021). Recent developments in water treatment by cellulose aerogels from agricultural waste. IOP Conference Series: Earth and Environmental Science, 947(­1), 12011. Park, S., Baker, J. O., Himmel, M. E., Parilla, P. A., & Johnson, D. K. (­2010). Cellulose crystallinity index: Measurement techniques and their impact on interpreting cellulase performance. Biotechnology for Biofuels, 3(­1), 10. Peng, B., Yao, Z., Wang, X., Crombeen, M., Sweeney, D. G., & Tam, K. C. (­2020). Cellulose-​­based materials in wastewater treatment of petroleum industry. Green Energy & Environment, 5(­1), 37–​­49. Phanthong, P., Reubroycharoen, P., Hao, X., Xu, G., Abudula, A., & Guan, G. (­2018). Nanocellulose: Extraction and application. Carbon Resources Conversion, 1(­1), 32–​­43. Pillai, S. S., Deepa, B., Abraham, E., Girija, N., Geetha, P., Jacob, L., & Koshy, M. (­2013). Biosorption of Cd(­II) from aqueous solution using xanthated nano banana cellulose: Equilibrium and kinetic studies. Ecotoxicology and Environmental Safety, 98, 352–​­360. Rodríguez Correa, C., Stollovsky, M., Hehr, T., Rauscher, Y., Rolli, B., & Kruse, A. (­2017). Influence of the carbonization process on activated carbon properties from lignin and lignin-​­rich biomasses. ACS Sustainable Chemistry & Engineering, 5(­9), 8222–​­8233. Sang, X., Qin, C., Tong, Z., Kong, S., Jia, Z., Wan, G., & Liu, X. (­2017). Mechanism and kinetics studies of carboxyl group formation on the surface of cellulose fiber in a TEMPO-​­mediated system. Cellulose, 24 (­6), 2415–​­2425. Seddiqi, H., Oliaei, E., Honarkar, H., Jin, J., Geonzon, L. C., Bacabac, R. G.,  & Klein-​­Nulend, J. (­2021). Cellulose and its derivatives: Towards biomedical applications. Cellulose, 28(­4), 1893–​­1931. Shen, Y., Ma, D., & Ge, X. (­2017). CO2-​­looping in biomass pyrolysis or gasification. Sustainable Energy & Fuels, 1(­8), 1700–​­1729. Silva Filho, E. C., Lima, L. C. B., Silva, F. C., Sousa, K. S., Fonseca, M. G.,  & Santana, S. A. A. (­2013). Immobilization of ethylene sulfide in aminated cellulose for removal of the divalent cations. Carbohydrate Polymers, 92(­2), 1203–​­1210. Singha, A. S., & Guleria, A. (­2014). Chemical modification of cellulosic biopolymer and its use in removal of heavy metal ions from wastewater. International Journal of Biological Macromolecules, 67, 409–​­417. Sivakumar, P., & Palanisamy, N. (­2010). Mechanistic study of dye adsorption on to a novel non-​­conventional low-​­cost adsorbent. Advances in Applied Science Research, 1(­1), 58–​­65.

Utilization of Cellulose in Wastewater Treatment

299

Sjahro, N., Yunus, R., Abdullah, L. C., Rashid, S. A., Asis, A. J., & Akhlisah, Z. N. (­2021). Recent advances in the application of cellulose derivatives for removal of contaminants from aquatic environments. Cellulose, 28(­12), 7521–​­7557. Sun, X., Peng, B., Ji, Y., Chen, J., & Li, D. (­2009). Chitosan(­chitin)/­cellulose composite biosorbents prepared using ionic liquid for heavy metal ions adsorption. AIChE Journal, 55(­8), 2062–​­2069. Wang, J., Geng, G., Liu, X., Han, F., & Xu, J. (­2016). Magnetically superhydrophobic kapok fiber for selective sorption and continuous separation of oil from water. Chemical Engineering Research and Design, 115, 122–​­130. Wang, Y., Liu, S., Wang, J., & Tang, F. (­2020). Polymer network strengthened filter paper for durable water disinfection. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 591, 124548. Wang, Y., Wang, X., Xie, Y., & Zhang, K. (­2018). Functional nanomaterials through esterification of cellulose: A review of chemistry and application. Cellulose, 25(­7), 3703–​­3731. Wanichapichart, P., Kaewnopparat, S., Buaking, K., & Puthai, W. (­2003). Characterization of cellulose membranes produced by acetobacter xyllinum. Songklanakarin Journal of Science and Technology, 24, 855–​­862. Williams, T., Hosur, M., Theodore, M., Netravali, A., Rangari, V., & Jeelani, S. (­2011). Time effects on morphology and bonding ability in mercerized natural fibers for composite reinforcement. International Journal of Polymer Science, 2011, 192865. World Water Assessment Programme (­United Nations), (­2018). The United Nations World Water Development Report 2018. United Nations Educational, Scientific and Cultural Organization, New York, USA. www. unwater.org/­publications/­world-​­water-​­development-​­report-​­2018/. Wu, F.-​­C., Tseng, R.-​­L., & Juang, R.-​­S. (­2010). A review and experimental verification of using chitosan and its derivatives as adsorbents for selected heavy metals. Journal of Environmental Management, 91(­4), 798–​­806. Yang, S., Fu, S., Liu, H., Zhou, Y., & Li, X. (­2011). Hydrogel beads based on carboxymethyl cellulose for removal heavy metal ions. Journal of Applied Polymer Science, 119(­2), 1204–​­1210. Yang, X., Reid, M. S., Olsén, P.,  & Berglund, L. A. (­2020). Eco-​­friendly cellulose nanofibrils designed by nature: Effects from preserving native state. ACS Nano, 14(­1), 724–​­735. Yu, X., Tong, S., Ge, M., Wu, L., Zuo, J., Cao, C., & Song, W. (­2013). Adsorption of heavy metal ions from aqueous solution by carboxylated cellulose nanocrystals. Journal of Environmental Sciences, 25(­5), 933–​­943. Zamora-​­Ledezma, C., Negrete-​­Bolagay, D., Figueroa, F., Zamora-​­Ledezma, E., Ni, M., Alexis, F., & Guerrero, V. H. (­2021). Heavy metal water pollution: A fresh look about hazards, novel and conventional remediation methods. Environmental Technology & Innovation, 22, 101504. Zhou, Y., Jin, Q., Hu, X., Zhang, Q., & Ma, T. (­2012). Heavy metal ions and organic dyes removal from water by cellulose modified with maleic anhydride. Journal of Materials Science, 47(­12), 5019–​­5029. Zwain, H. M., Vakili, M., & Dahlan, I. (­2014). Waste material adsorbents for zinc removal from wastewater: A comprehensive review. International Journal of Chemical Engineering, 2014, 347912.

21

Comparing Properties and Potential of Pinewood, Dried Tofu, and Oil Palm Empty Fruit Bunch (­EFB) Pellet as Cat Litter Noor Azrimi Umor, Nurul Hidayah Adenan, Nadya Hajar, Nurul Ain Mat Akil, and Nor Haniah A. Malik Universiti Teknologi MARA Cawangan Negeri Sembilan

Shahrul Ismail Universiti Malaysia Terengganu

Zaim Hadi Meskam Usaha Strategik Sdn. Bhd

CONTENTS Introduction..................................................................................................................................... 301 Materials.........................................................................................................................................302 Source of Biodegradable Cat Litter............................................................................................302 Methods...........................................................................................................................................302 Odor Recognition Test............................................................................................................... 303 Results and Discussion................................................................................................................... 305 Physical Properties..................................................................................................................... 305 Adsorption Rate, Total Volume of Water Adsorption, and Hydration Capacities...................... 305 Odor Sensory Test......................................................................................................................306 Conclusion......................................................................................................................................306 References.......................................................................................................................................307

INTRODUCTION In Malaysia, about 5 million cats were recorded in 2019, and 658,000 of them were adopted as pet (­Petfair, 2022).This is also contributed by the fact that 70% of the Malaysian population are pet owners (­Mordor Intelligence, 2022). Pets such as cats are reported to have a positive impact on various aspects of mental health and ­well-​­being, thus creating a better condition for coping with adverse situations such as movement control due to the COVID 19 pandemic (­Grajfoner et al., 2021). As a result, pet services have become one of the fastest growing business sectors, contributing to the increasing number of pet owners. It is a ­high-​­end industry that includes various services such as veterinarian, pet store, pet hotel, and others. Following this trend, the industry will continue to flourish in the coming years. It is reported that an average cat will secrete about 40 g of fecal waste every day (­Dabritz and Conrad, 2006). These feces and urine can be a nuisance due to their strong natural odor. Therefore, DOI: 10.1201/9781003358084-21

301

302

Cellulose

cat litter is commonly used for indoor or outdoor cat excretion to solve the problem (­Neilson, 2009). Cat litter must have the ability to absorb liquid and odor, making the waste easy to manage (­Saikeaw et al., 2021). Most commercial cat litters are imported and are either biodegradable or ­non-​­biodegradable. ­Non-​­biodegradable litter types include clay and crystal litter, while biodegradable litter types are based on cellulose and lignocellulosic materials such as pine, corn, paper cat litter, olive oil waste, and tofu (­Yarnell, 2004; Wendland, 2011; Wilde, 2022). It is estimated that for indoor cats, the amount of cat litter used per cat per month is in the range of ­4 –​­6 kg. The amount of waste generated from cat litter utilization in Malaysia may reached up to 1.316 million tons, given 50% of adopted cat are kept indoor. The use of biodegradable cat litter is more beneficial in terms of environmental risk while protecting cat and owner’s health. There is a possibility that cats will eat cat litter, and if it is not biodegradable, it may be toxic. When it comes to waste disposal, ­non-​ ­biodegradable cat litter is considered to be highly polluting and requires a special process compared to biodegradable types that are more environmentally friendly. For example, a clumping clay litter does not naturally decompose and cannot be flushed into either sewage or septic systems (­Vaughn et al., 2011). The use of empty fruit bunches (­EFB) pellets of oil palm as cat litter is new and has never been reported. EFB pellets are generally used as fuel pellets and have been found to be suitable for use as cat litter. EFB pellet is a lignocellulosic material mainly composed of plant cell walls consisted of cellulose, hemicellulose, and lignin. The ability to absorb water is determined by the structure of hydrophilic functional groups (­Wisetrat et al., 2012). In addition, cellulose has a structure and ion exchange with organic materials such as resin, which are also suitable as absorbents (­Saueprasearsit et al., 2010). Therefore, the use of lignocellulose as cat litter continues to spark interest. To produce pellets, EFB is mechanically and thermally treated to obtain a small, uniform size and a shorter, dry form compared to EFB fibers (­Umor et al., 2021). In terms of appearance, it has the normal shape of a commercial cat litter pellet. In addition, it is biodegradable, and the waste can even be safely disposed of on the ground or near plants. Although the material is marketed as cat litter and reportedly performs similarly to a commercial product, there is no scientific evidence to support this claim. In this study, the EFB pellet and EFB pellet + wood were evaluated for their properties as cat litter. Two types of commercial biodegradable cat litter, namely, pinewood and dried tofu, were also tested for comparison of performance. It is expected that the EFB pellet and EFB pellet + wood will provide a result comparable to the commercial product.

MATERIALS Source of Biodegradable Cat Litter Tofu and pine were purchased from a local pet shop in Kuala Pilah, Negeri Sembilan, while the EFB pellet was provided by EcoBed Sdn. Bhd., a local cat litter producer and supplier. All the samples were weighed prior to analysis. ­Table 21.1 shows the description of samples used in this study.

METHODS Physical property characterization The physical properties of cat litter including size, length, and diameter were measured using a digital caliper following the standard procedure. Moisture was calculated from differences in weight before and after the oven drying process, which was carried out for 24 h at 80°C. The pH of the samples were analyzed using a pH meter (­Merck). The bulk density was measured using the formula shown below:-​­

BD = (m2 − m1 )/Vc

Comparing Properties of Local and Commercial Cat Litter

303

TABLE 21.1 Description of Samples Sample

Description 100% EFB (6 mm)

EFB pellet Mix 80% EFB pellet and 20% wood

EFB pellet + wood 100% soya bean (tofu)

Dried tofu 100% natural pine wood

Wood

where BD is the bulk density (­g/­m−3), m2 is the weight of the filled container (­g), m1 is the weight of the empty container (­g), and V is the container volume (­m3) (­Brunerová et al., 2018). Absorption rate, water adsorption capacity, and hydration capacity The absorption rate of cat litter was calculated by measuring the time taken to absorb 100 mL of distilled water in a ­100-​­mL beaker using 50 g of the substrate. The setup of equipment and apparatus used are shown in ­Figure 21.1. For water adsorption capacity, 50 g of the substrate was placed in the beaker and a certain amount of water was added at one time until leaking. Hydration capacity was measured by dividing the total amount of water adsorption with the 50 g of samples. All tests were performed in triplicate.

Odor Recognition Test Four samples were used for this study: EFB pallet, EFB pallet + wood, wood, and dried tofu. The samples were stored in their original packaging at ambient temperature in a dry and odorless place until the sensory evaluation. Fifty panelists voluntarily participated in this study. The panelists were among undergraduate, postgraduate students, and UiTM staff. The panelists were compensated with a small gift for their participation in the study. The sensory evaluation was conducted in the sensory analysis laboratory, UiTM Cawangan Negeri Sembilan, Kampus Kuala Pilah. It is an individual sensory booth with white light. Before receiving the samples, the panelists were explained about the task and questionnaire. Then, they received the samples, which were coded with ­3-​­digit random numbers. The panelists rated their preferences using a scoring indicator, with “­1 = unable to identify,” “­2 = difficult to identify,” “­3 = easy to identify,” and “­4 = difficult

304

Cellulose

­FIGURE 21.1 

Water absorption rate test.

­FIGURE 21.2 

Sample of questionnaire given to the respondent.

to identify.” The panelists answered the questionnaire, choosing the sensory attributes that characterized their ideal sample. In this test, 5% of softener solution was prepared as odor reference solution. The sample is prepared by adding 10 mL of the reference solution to 10 g of samples. The respondents were required to recognize the smell of the softener from the sample using the scale sheet provided (­­Figure 21.2). Then, they were required to score each samples. ­One-​­way analysis of variance (­A NOVA) was used to analyze differences among the treatments. Comparison between different treatments was made using differences of least squares means, when significant ­F-​­test values from the ANOVA were obtained at p ≤ 0.05. All statistical analyses were performed using IBM SPSS Statistics version 19.

305

Comparing Properties of Local and Commercial Cat Litter

RESULTS AND DISCUSSION Physical Properties ­ able 21.2 shows the physical properties of the biomass sample. Dried tofu has the highest moisture T content compared to the other samples. However, there is not much difference between all samples in terms of moisture content. Dried tofu recorded the highest reading as 8%, followed by EFB pellet, EFB pellet + wood, and wood, which reported 6%, 4%, and 4%, respectively. It was expected that the pH of cat litter is generally almost neutral, but in this study, dried tofu was found to have an acidic pH of 4.53, while the other samples had a pH value of more than 6. The length of the samples showed that dried tofu and wood were longer, while the diameter of the wood and EFB pellet + wood samples was larger. Bulk density is defined as the ratio of the mass of biomass to its volume. The disadvantages of raw biomass are high moisture content, low bulk density, and thus lower heating value. Low bulk density leads to difficulties in handling, storing, and transporting the material (­Tang et al., 2014). From the results, the bulk density of dried tofu has a higher density than the other samples. This is expected as each material consists of different compositions and properties.

Adsorption Rate, Total Volume of Water Adsorption, and Hydration Capacities The absorption rate and total volume of water absorption of the samples ranged from 28.5 to 100 (­m L/­min) and ­100–​­131 mL, respectively, as shown in T ­ able 21.3. In addition, the hydration capacity of the tested samples ranged from 2.00 to 2.62 (­g water/­g litter). The hydration capacity recorded in this study was higher than previously reported. For example, only 0.­52–​­1.17 (­g water/­g litter) was measured for bentonite, while dried corn distiller can hold up to 2.17 (­g water/­g litter). In terms of total water retention volume for 50 g samples, wood was found to have the highest volume of

TABLE 21.2 Physical Properties of Pet Litter and Biochar Sample EFB pellet EFB pellet+ wood Dried tofu Wood

Moisture (%)

Length (mm)

Diameter (mm)

pH

Bulk Density (g m−3)

6 4 8 4

24.30 26.10 36.70 35.20

5.63 6.10 1.50 6.80

6.29 6.09 4.53 6.40

0.79 0.75 0.84 0.76

TABLE 21. 3 Absorption Rate, Total Volume of Water Adsorption, and Hydration Capacity of Cat Litter Sample EFB pellet EFB pellet+ wood Dried tofu Wood Bentonite (Cliff and Heymann, 1991) Flour pellet (Saikeaw et al., 2021) Corn dried distiller grains (Vaughn et al., 2011)

Absorption Rate (mL/ min) 28.5 100.0 40.0 70.42 – – –

Total Water Adsorption (mL) 100.00 113.33 110.00 131.00 26–58 27–39 108

Hydration Capacity (g water /g litter) 2.00 2.27 2.20 2.62 0.52–1.17 0.53–0.78 2.17

306

Cellulose

131 mL, followed by EFB pellet + wood with 113.33 mL. These were better than those in previous reports. It also shows that the tested biodegradable cat litter, especially EFB pellet, has sufficient quality compared to other types of commercial cat litter. For absorption rate, it was observed that EFB pellet + wood was the fastest absorbent compared to other samples. Combining wood with EFB pellet proves to be a good strategy to boost the absorption rate as EFB pellet alone only recorded 28.5 (­m L/­min) compared to the latter, 100 (­m L/­min). When these result were compared with the physical properties, it was observed that the lower bulk density did improve the absorption rate, and the lower moisture content of cat litter had increased the total water absorption.

Odor Sensory Test Odor can be evaluated by c­ hemical–​­analytical measurements or experiments and subjective odor analysis (­human perception). Subjective evaluation is a common tool for assessing the efficiency of odor reduction, e.g., in gas cleaning systems, to measure the ability to reduce the intensity and improve the hedonic odor of a gaseous effluent (­VDI, 1992). The result of the odor sensory test is shown in ­Table 21.4. In general, the score obtained by most respondents for all samples ranged from 1.80 to 2.06. This result indicates that all samples have good adsorption capacity for softener solution as the scores were classified as difficult to detect. Dried tofu was the best odor adsorbent, followed by wood and EFB pellet. The natural odor of the samples and the associated adsorption process contribute to the evaluation. Based on the physical properties, the acidic pH of tofu contribute to better adsorption of odor. Lower pH contribute to changes in substrate towards isoelectric point (­PI) thus possibly creating larger site of hydrophobic area to stretch and expose for better odor adsorption (­Xue et al., 2021). For example, when dried tofu was mixed with water only, it produced a natural odor that adsorb ­off-​­odors from detergent. When it reacted with the reference solution in the experiment, it surpassed the odor of the softener. Lignocellulosic materials such as wood and EFB pellets are considered ­low-​­cost biosorbents with natural affinity for inorganic and organic pollutants (­Ioannidov and Zabaniotou, 2007).

CONCLUSION In summary, the EFB pellet and EFB pellet + wood were found to be cat litter compared to commercial products, namely, wood and dried tofu. The overall result showed that both samples have suitable properties and comparable quality to dried tofu and wood. In some parameters, the samples outperform the commercial product. In terms of hydration capacity and the adsorption rate, the EFB pellet + wood was better than dried tofu and wood. The use of EFB pellets and EFB pellets + wood

TABLE 21.4 Mean of Score for Odor Recognition Test Sample EFB pellet EFB pellet + wood Dried tofu Wood

Odor Test Score 1.96c ± 0.83 2.06b ± 0.84 1.80a ± 0.97 1.92c ± 0.90

a,b,c  Different letters show significantly different among treatments (p < 0.05).

Comparing Properties of Local and Commercial Cat Litter

307

as cat litter is indeed a better choice for Malaysian people and could provide new income for the oil palm industry.

REFERENCES Brunerová, A., Roubík, H., & Brožek, M. (­2018). Bamboo fibre and sugarcane skin as a bio-​­briquette fuel. Energies, 11(­9), 2186. Cliff, M.,  & Heymann, H. (­1991). Descriptive analysis of oral pungency. Journal of Sensory Studies, 7(­4), 279–​­290. Dabritz, H. A & Conrad, P.A. (­2010). Cats and toxoplasma: Implications for public health. Zoonoses Public Health, 57, 34–​­52. Grajfoner, D., Ke, G. N., & Wong, R. (­2021). The effect of pets on human mental health and wellbeing during COVID-​­19 lockdown in Malaysia. Animals, 11(­9), 2689. Ioannidou, O., & Zabaniotou, A. (­2007). Agricultural residues as precursors for activated carbon production-​­A review. Renewable and Sustainable Energy Reviews, 11(­9), 1966–​­2005. Mordor Intelligence. (­2022). Malaysia pet food market -​­Growth, trends, COVID-​­19 impact, and forecasts (­2022–​ 2­ 027). Assessed on 20 June 2022 at https://­www.mordorintelligence.com/­industry-​­reports/­malaysia​­petfood-​­market. Neilson, J. C. (­2009). The latest scoop on litter. Journal of Veterinary Medicine, 104, 140–​­144. Petfair. (­ 2022). Malaysia pet market insights. Accessed on 28 June 2022 at https://­ www.petfair-​­ sea. com/­asia-​­markets/­southeast-​­asia-​­pet-​­market/­malaysia-​­pet-​­market/. Saikeaw, N., Rungsardthong, V., Pornwongthong, P., Vatanyoopaisarn, S., Thumthanaruk, B., Pattharaprachayakul, N., Wongsa, J., Mussatto, S. I., & Uttapap, D. (­2021). Preparation and properties of biodegradable cat litter produced from cassava (­Manihot esculenta L. Crantz) trunk. E3S Web of Conferences, 302, 02017. Saueprasearsit P., Nuanjarae, M. & Chinlapa M. (­2010). Biosorption of lead (­Pb2+) by Luffa cylindrical fibre. Environmental Research Journal, 4(­1), 157–​­166. Tang, J. P., Lam, H. L., Aziz, M. K. A., & Morad, N. A. (­2014), Biomass characteristics index: A numerical approach in palm bio-​­energy estimation. Computer Aided Chemical Engineering, 33, 1093–​­1098. Umor, N. A., Abdullah, S., Mohamad, A., Ismail, S. Bin, Ismail, S. I., & Misran, A. (­2021). Energy potential of oil palm empty fruit bunch (­Efb) fibre from subsequent cultivation of Volvariella volvacea (­bull.) singer. Sustainability, 13(­23), ­1–​­15. Vaughn, S. F., Berhow, M.A., Winkler-​­Moser, J.K., & Lee, E. (­2011). Formulation of a biodegradable, odour-​ ­reducing cat litter from solvent-​­extracted corn dried distillers grains. Industrial Crops and Products, 34(­1), 999–​­1002. VDI. (­1992). VDI 3882 Part 2. O ­ lfactometry -​­Determination of Hedonic Odour Tone. Düsseldorf: Verein Deutscher Ingenieure (­VDI). Wendland. (­2011). A thesis: Development of a novel cat litter from olive oil waste products. Master of Animal Science, Graduate College, Massy University. Wilde, L. (­2022). The 6 best eco-​­friendly cat litters of 2022. Accessed on 22 June 2022 at https://­www.treehugger.com/­best-​­eco-​­friendly-​­cat-​­litter-​­5180604. Wisetrat, O., Ngamsombat, R., Saueprasearsit, P.,  & Prasara, J. (­2012). Adsorption of suspended oil using bagasse and modified bagasse. Journal of Science and Technology Mahasarakham University, 31, 4. Xue, C., You, J., Zhang, H., Xiong, S., Yin, T., & Huang, Q. (­2021). Capacity of myofibrillar protein to adsorb characteristic fishy-​­odor compounds: Effects of concentration, temperature, ionic strength, pH and yeast glucan addition. Food Chemistry, 363, 130304. Yarnell, A. (­2004). Kitty litter. Chemical & Engineering News, 82, 26.

22

Challenges and Future Perspectives Junidah Lamaming, Abu Zahrim Yaser and Mohd Sani Sarjadi Universiti Malaysia Sabah

CONTENT References....................................................................................................................................... 311 A molecule called cellulose is made up of hundreds, and occasionally even thousands, of carbon, hydrogen, and oxygen atoms. Cellulose is no longer associated with typical applications as it is emerging as the most flexible and smart material. Considering its excellent mechanical strength, biocompatibility, biodegradability, and environmental friendliness, cellulose has evolved as an intriguing material for a variety of applications (­­Figure 22.1). Cellulose is indeed remarkable when its properties are tuned in the right direction. As research studies have deepened and expanded with the advancement of technology and innovation, some of the challenges encountered and addressed for the sustainability of the cellulose in the developments, processing, or applications. Some of reviews has highlighted the concerns regarding the ­cellulose-​­based materials in various field such as in packaging (­Nadeem et al., 2022; Shi et al., 2023), medical (­Thomas et al., 2020; Ji et al., 2022), water treatments (­Aoudi et al., 2022), composites (­Trache et al., 2022) and as an adsorbents (­Zhang et al., 2023), among others. One strategy to secure future energy that is ecologically beneficial is to produce biofuel from a variety of renewable biomass feedstocks in place of fossil fuels. Two potential conversion ­pathways—​ ­thermochemical and biochemical conversion ­pathways—​­have been emphasized in order to ensure the biofuel production’s success. Different conversion pathways will result in different products depending on the application. A wide variety of chemical distribution in various feedstocks is also obviously capable of influencing the final biofuel product in terms of both quality and quantity. Therefore, choosing the best feedstock for the intended use is crucial. The stability of the product is another factor that must be taken into account before being utilized as fuel. To solve this problem, more advancements in ­bio-​­oil and new technology are needed. Currently, the biochemical conversion route used to create biofuels like ethanol and butanol requires numerous steps. Further research into using strong microorganisms to convert syngas or hydrogen from a thermochemical pathway may offer a substitute to reduce the number of steps required in the process. On the other hand, creating ­single-​­step processes that combine fermentation and hydrolysis or do both at once could help guarantee the creation of biofuel. To assure the viability of future biofuel production, further research is needed to attempt the maximum biofuel production from a variety of feedstocks using ­low-​­energy and affordable technology. Lignocellulosic biomass, which includes waste from oil palm trees and bamboo, is a plentiful source of energy that enables the production of a wide range of useful products, including pulp, paper, biodiesel, and palm composite. It offers great adaptability in terms of feedstock that can be sampled and can be operated in a wide range of temperatures and weather situations. Bamboo biomass can be processed by a number of methods, including pyrolysis, gasification, and thermal conversion, to produce fuel. The commercially feasible byproducts of the processes are ethanol, oil, syngas, charcoal, and syngas. The fuel characteristics of bamboo biomass are superior to those of most energy crops. It might be able to grow on ruined soil with less upkeep and less competition DOI: 10.1201/9781003358084-22

309

310

Cellulose Extraction Processing

•Bamboo/ Wood/ Plants/ Cotton/ Bacteria/ Animal Sources

Primary processing Structure

Forms

•Cellular cellulose/ Pulp/ Regenerated cellulose/ Cellulose nanomaterials/ Cellulose derivatives/ Cellulosic chemicals

Secondary processing Properties

Products

Tertiary processing Performance

Application

•Composites/ fibers/ hydrogels/aerogels/ membranes/ films/ paper •Consumables/ packaging/ textiles/ construction/ coatings/ automotive

F­ IGURE 22.1  Diagram show the processing, structure, and discoveries about the characteristics and uses of cellulose.

from food crops for space. Despite the fact that palm oil has a wide range of applications, the palm oil industry has recently come under heavy criticism due to a number of environmental and social problems. Although the oil palm industry waste is surrounded by a number of difficulties, it also offers a number of opportunities in terms of products that can be made from it, particularly as it can be used as a renewable energy to aid in the growth of a country. Large amounts of nutrients are present in oil palm biomass, and the nutrient profiles from earlier studies have revealed that this biomass could be used as ­bio-​­compost and organic fertilizer, helping to condition the soil and lowering the use of inorganic fertilizer in agriculture sectors while also lowering the environmental impact. The importance of ­re-​­cultivation using reused compost still needs to be further investigated (­Umor et al., 2021). Depending on the required ratio, mixing palm oil waste with other organic wastes could hasten the composting process and boost the macronutrients and micronutrients in the compost for use as a growing medium, particularly for horticulture plants. Different types of industrial wastewater utilized as nutrient enhancers and moisturizers demonstrated varying performances in the production of compost. Utilizing household wastewater and other types of industrial wastewater as fertilizer boosters and moisturizers in composting should be the subject of further study. Therefore, bioconversion of palm oil wastes needs to be a strong plan and policy to be followed in future in order to achieve optimal palm oil production in a more sustainable manner. Unquestionably, advanced biomaterials have a greater impact on the world economy by enabling the production of ­energy-​­saving products that improve living standards. Study in this field is beneficial because there are so many issues that still need to be resolved. Undoubtedly, with the right design and choice of production technique, biocomposites will dominate the structural materials market in the engineering sector. Combining natural fibers with polymers generated from renewable resources can help solve several environmental issues. To promote worldwide growth in this ­cutting-​­edge class of materials for positive societal, environmental, and economic advantages, industry leaders and senior government officials must work together. In addition to the benefits of composites made from renewable and sustainable materials in terms of economics and functionality, these leaders’ leadership is necessary. Apart from that, the increasing number of research conducted and published in replacing vehicle parts with natural fiber composites makes a significant contribution to the automotive industry. However, great effort must be placed in order to convince the consumers about the reliability of this natural ­fiber-​­reinforced composites in automotive sectors since many are still having doubts about its performance in comparison to conventional materials. With all factors being taken into account, the breakthrough of excellent potential of these natural

Challenges and Future Perspectives

311

fiber composites for automotive application would finally contribute to improvements in societal ­well-​­being and eventually meet the requirement of sustainable development goal. Can ­cellulose-​­based composites compete in terms of characteristics with classic synthetic materials? The use of nanomaterials in cement composite materials, notably the use of cellulose nanocrystals (­CNCs) as a strengthening agent, has attracted considerable interest in the construction industry. Despite that, only a few researchers have explored the impact of CNCs on the strength of cement composites (­compressive, flexural, and tensile). The reasons behind how CNCs respond and enhance the cement matrix structure, however, are still being investigated. Research on sustainable construction materials has recently received a lot of attention. Additionally, there has been an increase in demand for “­green” materials with desirable thermal properties, particularly in tropical nations. Currently, research on CNCs’ thermal performance indicates that they have a strong chance of serving as the cooling agent in cement composites. One of the significant research gaps that have to be filled involves CNCs as the cooling agent in the cement matrix. In addition, the hybrid composites created by blending nanocellulose with other nanomaterials like graphene offer a variety of opportunities to create ­high-​­quality composites for next research. The most applauding applications of c­ ellulose-​­based materials are their melted form. With the right control and effective regeneration mechanisms, the dissolved state can be used for a plethora of applications with even the most complicated structures. Numerous surface alterations are possible, thanks to the presence of hydroxyl functional groups on nanocellulose surfaces, creating advantageous nanocomposites with adjustable properties. Materials composed of cellulose are appealing in a wide range of applications due to their interchangeable size, form, and texture. According to the desired use, the physical, mechanical, thermal, and biological characteristics can be ­pre-​­designed and fabricated. The compatibility with different materials vastly improves the quality of items made from regenerated cellulose. In ­cellulose-​­based research and fields, there is still potential for further discoveries and fundamental information in terms of advanced technology and engineering development. Superhydrophobic membranes, 3D bioprinting technologies, and superabsorbents are some of the numerous newly developing and growing fields that will help a wide range of industries. One of the most discussed challenges in the cellulose research is the cost of producing cellulose from raw materials to commercialization. ­Large-​­scale cellulose isolation can be an ­energy-​­and ­time-​­intensive procedure. Recent technological advancements have made it possible to manufacture nanocellulose mechanically or chemically, and only a select few businesses and research facilities are currently able to do so in considerable quantities on a pilot scale. Nanocellulose has the tendency to irrevocably agglomerate upon drying, making it difficult to handle and store it while keeping its nanoscale structure. Agglomeration has an impact on the cellulose fibril size distribution, which results in a loss of impacts on the material’s nanoscale properties. Obtaining sufficient amounts of dry cellulose nanofibrils in a n­ on-​­agglomerated condition is challenging. Both the manufacturing procedure utilized to remove water from the nanocellulose suspensions and the specific nanocellulose manufacturing technique can have an impact on fibril morphology. The surface modification and redispersibility of nanocellulose may be important variables for better transportation and l­ong-​ ­term application. Comprehensive and systematic investigations are still required to utilize products beyond the laboratory scale and for commercialization in order to enhance understanding and enable ­high-​­throughput production (­Aoudi et al., 2022; Barhoum et al., 2022).

REFERENCES Aoudi, B., Boluk, Y., & El-​­Din, M.G. (­2022). Recent advances and future perspective on nanocellulose-​­based materials in diverse water treatment applications. Science of the Total Environment, 843, 156903. Barhoum, A., Rastogi, V.K., Mahur, B.K., Rastogi, A., Abdel-​­Haleem, F. M., & Samyn, P. (­2022). Nanocelluloses as new generation materials: Natural resources, structure-​­related properties, engineering nanostructures, and technical challenges. Materials Today Chemistry, 26, 101247.

312

Cellulose

Ji, F., Sun, Z., Hang, T., Zheng, J., Li, X., Duan, G., Zhang, C., & Chen, Y. (­2022). Flexible piezoresistive pressure sensors based on nanocellulose aerogels for human motion monitoring: A review. Composites Communications, 35, 101351. Nadeem, H., Athar, M., Dehghani, M., Garnier, G.,  & Batchelor, W. (­2022). Recent advancements, trends, fundamental challenges and opportunities in spray deposited cellulose nanofibril films for packaging applications. Science of the Total Environment, 836, 155654. Shi, J., Zhang, R., Liu, X., Zhang, Y., Du, Y., Dong, H., Ma, Y., Li, X., Cheung, P. C.K., & Chen, F. (­2023). Advances in multifunctional biomass-​­derived nanocomposite films for active and sustainable food packaging. Carbohydrate Polymers, 301(­Part B), 120323. Thomas, P., Duolikun, T., Rumjit, N.P., Moosavi, S., Lai, C. W., Johan, M. F.,  & Fen, L.B. (­ 2020). Comprehensive review on nanocellulose: Recent developments, challenges and future prospects. Journal of the Mechanical Behavior of Biomedical Materials, 110, 103884. Trache, D., Tarchoun, A. F., Abdelaziz, A., Bessa, W., Hussin, M.H., Brossed, O.C., & Thakur, V.K. (­2022). Cellulose nanofibrils–​­graphene hybrids: Recent advances in fabrication, properties, and applications. Nanoscale, 14, 12515–​­12546. Umor, N.A., Ismail, S., Abdullah, S. Huzaifah, M.H. R., Huzir, N. M., Mahmood, N.A.N., & Zahrim, A.Y. (­2021). Zero waste management of spent mushroom compost. Journal of Material Cycles and Waste Management, 23, 1726–​­1736. Zhang, Z., Abidi, N., Lucia, L., Chabi, S., Denny, C. T., Parajuli, P., & Rumi, S.S. (­2023). Cellulose/­nanocellulose superabsorbent hydrogels as a sustainable platform for materials applications: A ­mini-​­review and perspective. Carbohydrate Polymers, 299, 120140.

Index absorption 228, 263, 303 additives 132, 188, 231, 242, 261 aerogels 30, 223 all-cellulose 4, 145, 157 application 110, 126, 153, 181, 225, 280 automotive 109, 126, 228 bagasse 47, 202, 207 bamboo 8, 139, 195 bioadhesives 164, 169 biochemical 19, 28, 57, 61, 309 biocomposite 105, 110 biofuel 16, 46, 61 biomass 27, 32, 57, 61, 309 biomedical 188, 225 bioprinting 226, 242, 311 bulking agents 93, 95 cellulose nanocrystals 3, 135, 203, 208, 311 cellulose nanofibers 188, 243 challenges 97, 114, 170 composites 122, 150, 153, 167, 170, 226, 281 composting 2, 76–77, 84, 98 crosslinking 168, 170, 221, 240, 242 cryogel 221, 223 decorative 110 dissolution 146, 150, 218, 220, 230, 291 drug delivery 226, 241 empty fruit bunch 54, 76, 87, 90, 302 enzymatic 59, 137, 192, 205 fermentation 38, 61, 63, 108 fertilizer 76, 97, 227, 310 finishing 230, 279 halophilic 34–36 hydrogels 154, 221, 226, 238 hydrolysis 59, 140, 179, 190, 205, 212, 241–244 impregnation 147

leather 277, 280 lignocellulosic materials 1, 27, 63, 106, 186, 269, 302 liquefaction 53 matrix 12, 114, 121, 125, 145, 147, 194 mechanical 122, 132, 140, 148, 153, 193, 208, 224, 258, 274 membrane 219, 224, 226, 289 modification 107, 140, 166, 208, 290, 311 nanocellulose 140, 167, 169, 187, 196, 238 nutrient 87, 95, 182, 227–228 oil palm 27, 71 oxidation 212, 292 packaging 153, 181, 182 papermaking 256, 263, 270 pellet 302, 306 polyhydroxyalkanoates 108, 179, 182 polylactic acids 108 polymers 106, 109, 110, 122, 178, 219, 245, 293 pretreatment 31, 57, 189, 191, 204 recovery 256 regeneration 154, 218, 220, 243 reinforcement 108, 122, 145, 147, 170, 230 scaffolds 154, 226, 242 structural 109, 132 sugarcane 47, 187, 195, 201 sustainability 119, 154, 310 tanning 279 thermochemical 27, 47, 64 thermoplastic 114, 123, 125, 229 thermoset 111, 125 tissue engineering 154, 182, 226, 242 vermicomposting 91, 93 wastewater 8, 93, 98, 156, 177, 287, 294 wound dressing 225, 243 xerogels 221, 223

313

Taylor & Francis eBooks www.taylorfrancis.com A single destination for eBooks from Taylor & Francis with increased functionality and an improved user experience to meet the needs of our customers. 90,000+ eBooks of award-winning academic content in Humanities, Social Science, Science, Technology, Engineering, and Medical written by a global network of editors and authors.

TAYLOR & FRANCIS EBOOKS OFFERS: A streamlined experience for our library customers

A single point of discovery for all of our eBook content

Improved search and discovery of content at both book and chapter level

REQUEST A FREE TRIAL [email protected]